Äðóãîå : The history of railways (Èñòîðèÿ æåëåçíûõ äîðîã)
The history of railways (Èñòîðèÿ æåëåçíûõ äîðîã)
The history
of railways
The railway is à good example of à system
evolved in variousplaces to fulfil à need and then developed empirically. In essence
it consists îf parallel tracks or bars of metal or wood, supported
transversely by other bars — stone, wood, steel and concrete
have been used — so that thå load of the vehicle is spread
evenly through the substructure. Such tracks were used in
the Middle Ages for mining tramways in Europe; railways
came to England in the 16th century and went back to Europe
in the 19th century as an English invention.
English railways
The first Act of Parliament for à railway, giving
right of way over other people's property, was passed
in 1758,
and the first for à public railway, to carry the traffic of all
comers, dates from 1801. The Stockton and Dailington Railway,
opened on 27 September 1825, was the first public steam
railway in the world, although it had only one locomotive
and relied on horse traction for the most part, with
stationary steam engines for working inclined planes.
The obvious advantages of railways as à means of
conveying heavy loads and passengers brought about à
proliferation of projects. The Liverpool & Manchester, 30
miles (48 km) long and including formidable engineering problems,
became the classic example of à steam railway for general
carriage. It opened on 15 September 1830 in the presence of
the Duke of Wellington, who had been Prime Minister until earlier
in the year. On opening day, the train stopped for water and
the passengers alighted on to the opposite track; another
locomotive came along and William Huskisson, an ÌÐ and à great advocate
of the railway, was killed. Despite this tragedy the railway
was à great success; in its first year of operation, revenue
from passenger service was more than ten times that anticipated.
Over 2500 miles of railway had been authorized in
Britain and nearly 1500 completed by 1840.
Britain presented the world with à complete system for
the construction and operation of railways. Solutions were
found to civil engineering problems, motive power designs
and the details of rolling stock. The natural result of these
achievements was the calling in of British engineers to
provide railways in France, where as à consequence left-hand
rujning is still in force over many lines.
Track gauges
While the majority of railways in Britain adopted
the 4 ft 8.5 inch (1.43 m) gauge of the Stockton &
Darlington
Railway, the Great Western, on the advice of its brilliant
but eccentric engineer Isambard Kingdom Brunel, had
been laid to à seven foot (2.13 m) gauge, as were many of its
associates. The resultant inconvenience to traders caused the
Gauge of Railways Act in 1846, requiring standard gauge on all
railways unless specially authorized. The last seven-foot gauge
on the Great Western was not converted until 1892.
The narrower the gauge the less expensive the
construction and maintenance of the railway; narrow gauges
have been common in underdeveloped parts of the world and in
mountainous areas. In 1863 steam traction was applied to the 1 ft 11.5 inch (0.85
m) Festiniog Railway 1n Wales, for which locomotives were built
to the designs of Robert Fairlie. Íå
then led à campaign for the
construction of narrow gauges. As à result of the export of English
engineering and rolling stock, however, most North American and
European railways have been built to the standard gauge, except
in Finland and Russia, where the gauge is five feet (1.5
m).
Transcontinental lines
The first public
railway was opened in America in 1830, after which rapid
development tookplace. À famous 4-2-0 locomotive called the Pioneer
first ran from Chicago in 1848, and that city became one of
the largest rail centres in the world. The Atlantic and
the Pacific oceans were first linked on 9 Ìàó 1869, in à famous
ceremony at the meeting point of the Union Pacific and Central
Pacific lines at Promontory Point in the state of Utah. Canada
was crossed by the Canadian Pacific in 1885; completion of
the railway was à condition of British Columbia joining
the Dominion of Canada, and considerable land concessions
were granted in virtually uninhabited territory.
The
crossing of Asia with the Trans-Siberian Railway was begun
by the Russians in 1890 and completed in 1902, except for à
ferry crossing Lake Baikal. The difficult passage round the
south end of the lake, with many tunnels, was completed in 1905.
Today more than half the route is electrified. In 1863 the
Orient Express ran from Paris for the first time and eventually
passengers were conveyed all the way to Istanbul (Constantinople).
Rolling stock
In the early days,
coaches were constructed entirely of wood, including the frames. Âó
1900, steel frames were commonplace; then coaches were
constructed entirely of steel and became very heavy. One American
85-foot (26 m) coach with two six-wheel bogies weighed more
than 80 tons. New lightweight steel alloys and aluminium
began
to be used; in the
1950s the Budd company in America was
building an
85-foot coach which weighed only 27 tons. The savings
began with the bogies, which were built without conventional
springs, bolsters and so on; with only two air springs
on each four-wheel bogie, the new design reduced the weight
from 8 to 2,5 tons without loss îf strength or stability.
In
the I880s, 'skyscraper' cars were two-storey wooden vans
with windows used as travelling dormitories for railway workers
in the USA; they had to be sawn down when the railways
began to build tunnels through the mountains. After
World War II double-decker cars of à mîrå compact design
were built, this time with plastic domes, so that passengers could enjoy the
spectacular scenery on the western
lines, which pass through the
Rocky Mountains.
Lighting
on coaches was by means of oil lamps at first; then gas
lights were used, and each coach carried à cylinder îf gas, which
was dangerous in the event of accident or derailment. Finally
dynamos on each car, driven by the axle, provided electricity,
storage batteries being used for when the car was standing. Heating
on coaches was provided in the early days
by metal
containers filled with hot water; then steam was piped
from the locomotive, an extra drain on the engine's power;
nowadays heat as well as light is provided electrically.
Sleeping
accommodations were first made on the Cumberland Valley Railroad in the United
States in 1837. George Pullman's first cars ran on the Chicago &
Alton Railroad in 1859 and the Pullman Palace Car Company was
formed in 1867. The first Pullman cars operated in Britain in
1874, à year after the introduction of sleeping cars by two
British railways. In Europe in 1876 the International Sleeping
Car Company was formed, but in the meantime George Nagelmackers
of Liege and an American, Col William D'Alton Ìànn, began
operation between Paris and Viennain 1873.
Goods
vans [freight cars] have developed according to the needs
of the various countries. On the North American continent,
goods trains as long as 1,25 miles are run as far as 1000
miles unbroken, hauling bulk such as raw materials and foodstuffs.
Freight cars weighing 70 to 80 tons have two four wheel
bogies. In Britain, with à denser population and closely
adjacent towns, à large percentage of hauling is of small
consignments of manufactured goods, and the smallest goods
vans of any country are used, having four wheels and, up to
24,5 tons capacity. À number of bogie wagons are used for
special purposes, such as carriages fîr steel rails, tank cars for
chemicals and 50 ton brick wagons.
The
earliest coupling system was links and buffers, which allowed
jerky stopping and starting. Rounded buffers brought snugly
together by adjustment of screw links with springs were an
improvement. The buckeye automatic coupling, long standard
in North America, is now used in Britain. The coupling
resembles à knuckle made of steel and extending horizontally;
joining àuîtomàtika11ó with the coupling of the next
ñàr when pushed together, it is released by pulling à pin.
The
first shipment of refrigerated goods was in 1851 when butter
was shipped from New York to Boston in à wooden van
packed with ice and insulated with sawdust. The bulk of refrigerated
goods were still carried by rail in the USA in the, 1960s,
despite mechanical refrigeration in motor haulage; because
of the greater first cost and maintenance cost of mechanical
refrigeration, rail refrigeration is still mostly
provided by vans
with ice packed in end bunkers, four to six inches (10 to 15 cm) of insulation
and fans to circulate the cool air.
Railways in wartime
The first war in which railwaysfigured prominently
was the American
Civil War (1860-65), in which the Union
(North) was better
able to organize andmake use of its railways than the Confederacy (South). The war
was marked by à famous incident in which à 4-4-0 locomotive
called the General
was hi-jacked by Southern agents.
The outbreak of
World War 1 was caused in part by the
fact that the
mobilization plans of the various countries, including
the use îf railways and rolling stock, was planned to the last detail, except
that there were nî provisions for stopping the plans once they had been put
into action until the armies were facing each other. In 1917 in the United
States, the lessons of the Civil War had been forgotten, and freight vans were
sent to their destination with nî facilities for unloading, with the result
that the railways were briefly taken over by the government for the only time
in that nation's history.
In
World War 2, by contrast, the American railways performed magnificently,
moving 2,5 times the level of freight in 1944 as in 1938, with
minimal increase in equipment, and
supplying more than 300,000
employees to the armed forces in various capacities. In combat areas, and in
later conflicts such as the Korean war, it proved difficult to
disrupt an enemy's rail system effectively; pinpoint bombing was difficult,
saturation bombing was expensive and in any case railways
were quickly and easily repaired.
State railways
State intervention began in England withpublic
demand for safety regulation which resulted in Lord
Seymour's Act in 1840; the previously mentioned Railway
Gauges Act followed in 1846. Ever since, the railways
havebeen recognized as one of the most important of nationalresources
in each country.
In France, from 1851 onwards concessions were granted
for a planned regional system for which the Government provided ways
and works and the companies provided track and roiling stock; there was
provision for the gradual taking over of the lines by the State, and the Societe
Nationale des Chemins de Fer Francais (SNCF) was formed in 1937 as à company
in which the State owns 51% of the capital and theompanies 49%.
The Belgian Railways were planned by the State from
the outset in 1835. The Prussian State Railways began in
1850; bó the end of the year 54 miles (87 km) were open.
Italian and Netherlands railways began in 1839; Italy nationalized
her railways in 1905-07 and the Netherlands in the period 1920-38.
In Britain the main railways were nationalized from 1
January 1948; the usual European pattern is that the State owns
the main lines and minor railways are privately owned or
operated by local authorities.
In the United States, between the Civil War and World Wàr 1
the railways, along with all the other important inndustries,
experienced phenomenal growth as the country developed.
There were rate wars and financial piracy during à
period of growth when industrialists were more powerful than
the national government, and finally the Interstate Commerce
Act was passed in l887 in order to regulate the railways,
which had à near monopoly of transport. After World
War 2 the railways were allowed to deteriorate, as private
car ownership became almost universal and public money
was spent on an interstate highway system making motorway
haulage profitable, despite the fact that railways are
many times as efficient at moving freight and passengers. In the
USA, nationalization of railways would probably require
an amendment to the Constitution, but since 1971 à government
effort has been made to save the nearly defunct passenger
service. On 1 May of that year Amtrack was formed by the
National Railroad Passenger Corporation to operate à skeleton
service of 180 passenger trains nationwide, serving 29
cities designated by the government as those requiring train
service. The Amtrack service has been heavily used, but
not adequately
funded by Congress, so that bookings,
especially for
sleeper-car service, must be made far in
advance.
The locomotive
Few machines in the machine age have inspired so much
affection as railway locomotives in their 170 years of operation. Railways
were constructed in the sixteenth century, but the wagons were drawn by
muscle power until l804. In that year an engine built by Richard Trevithick worked
on the Penydarren Tramroad in South Wales. It broke some cast iron tramplates,
but it demonstrated that steam could be used for haulage,
that steam generation could be stimulated by turning
the exhaust steam up the chimney to draw up the fire, and that smooth
wheels on smooth rails could transmit motive power.
Steam locomotives
The steam locomotive is à robust and
simple machine.
Steam is admitted to à cylinder and by
expanding pushes
the piston to the other end; on the return
stroke à port opens to clear the
cylinder of the now expanded steam. By means of mechanical coupling, the
travel of the piston turns the drive wheels of the
locomotive.
Trevithick's engine was put to work as à stationary
engine at Penydarren. During the following twenty-five years,
à limited number of steam locomotives enjoyed success on colliery
railways, fostered by the soaring cost of horse fodder towards
the end of the Napoleonic wars. The cast iron plateways, which
were L-shaped to guide the wagon wheels, were not strong enough to
withstand the weight of steam locomotives, and
were soon replaced by smooth rails and flanged wheels on the rolling
stock.
John
Blenkinsop built several locomotives for collieries, which
ran on smooth rails but transmitted power from à toothed wheel to à rack
which ran alongside the running rails. William Hedley was building
smooth-whilled locomotives which ran on plateways, including the first to
have the popular nickname Puffing Billy.
In 1814 George Stephenson began building for smooth
rails at Killingworth, synthesizing the experience of the earlier designers.
Until this time nearly all machines had the cylinders
partly immersed in the boiler and usually vertical. In 1815
Stephenson and Losh patented the idea of direct drive
from the cylinders by means of cranks on the drive wheels
instead of through gear wheels, which imparted à jerky
motion, especially when wear occurred on the coarse gears.
Direct drive allowed à simplified layout and gave greater
freedom to designers.
In 1825 only 18 steam locomotives were doing useful
work. One of the first commercial railways, the Liverpool
& Manchester, was being built, and the directors had still not decided
between locomotives and ñàblå haulage, with railside steam
engines pulling the cables. They organized à competition which
was won by Stephenson in 1829, with his famous engine, the Rocket,
now in London's Science Museum.
Locomotive boilers had already evolved from à simple
flue to à
return-flue type, and then to à tubular design, in which à
nest of fire tubes, giving more heating surface, ran from
the firebox tube-plate to à similar tube-plate at the smokebox
end. In the smokebox the exhaust steam from the cylinders
created à blast on its way to the chimney which kept
the fire up when the engine was moving. When the locomotive
was stationary à blower was used, creating à blast
from à ring îf perforated pipe into which steam was directed.
À further development, the multitubular boiler, was
patented by Henry Booth, treasurer of the Liverpool & Manchester,
in 1827. It was incorporated by Stephenson in the Rocket,
after much trial and error in making the ferrules of the
copper tubes to give water-tight joints in the tube
plates.
After 1830 the steam locomotive assumed its familiar
form, with the cylinders level or slightly inclined at the
smokebox end and the fireman's stand at the firebox end.
As soon as the cylinders and axles were nî longer fixed in or
under the boiler itself, it became necessary to provide à frame
to hold the various components together. The bar frame
was used on the early British locomotives and exported to
America; the Americans kept ñî the bar-frame design, which
evolved from wrought iron to cast steel construction, with
the cylinders mounted outside the frame. The bar frame was
superseded in Britain by the plate frame, with cylinders inside
the frame, spring suspension (coil or laminated) for the
frames and axleboxes (lubricated bearings) to hold the
axles.
As British railways nearly all produced their own
designs, à great many characteristic types developed. Some
designs with cylinders inside the frame transmitted the motion
to crank-shaped axles rather than to eccentric pivots on
the outside of the drive wheels; there were also compound locomotives,
with the steam passing from à first cylinder or cylinders
to another set of larger ones.
When steel came into use for building boilers after
1860, higher operating pressures became possible. By the end
of the nineteenth century 175 psi (12 bar) was common,
with 200 psi (13.8 bar) for compound locomotives. This rose
to 250 psi (17.2 bar) later in the steam era. (By
contrast, Stephenson's Rocket only developed 50 psi, 3.4
bar.) In the l890s express engines had cylinders up to 20
inches (51 cm) in diameter with à 26 inch (66 cm) stroke.
Later diameters increased to 32 inches (81 cm) in places like
the USA, where there was more room, and locomotives and
rolling stock in general were built larger.
Supplies of fuel and water were carried on à separate tender,
pulled behind the locomotive. The first tank engine carrying
its own supplies, appeared tn the I830s; on the continent
of Europe they were. confusingly called tender engines.
Separate tenders continued to be common because they
made possible much longer runs. While the fireman stoked
the firebox, the boiler had to be replenished with water
by some means under his control; early engines had pumps
running off the axle, but there was always the difficulty that the
engine had to be running. The injector was
invented in 1859. Steam from the
boiler (or latterly, exhaus steam) went through à cone-shaped jet and
lifted the water into the boiler against the greater pressure there
through energy imparted in condensation. À clack (non-return
valve)
retained the steam
in the boiler.
Early
locomotives burned wood in America, but coal in Britain. As British
railway Acts began to include penalties for
emission of dirty black smoke,
many engines were built after 1829 to burn coke. Under Matthetty Kirtley on
the Midland Railway the brick arch in the firebox and deflector
plates were developed to direct the hot gases from the coal
to pass over the flames, so that à relatively clean blast came
out of
the chimney and
the cheaper fuel could be burnt. After 1860 this
simple expedient was universà11ó adopted. Fireboxes were
protected by being surrounded with à water jacket; stays
about four inches (10 cm) apart supported the inner firebox
from the outer.
Steam was
distributed to the pistons by means of valves. The
valve gear provided for the valves to uncover the ports at
different parts of the stroke, so varying the cut-off to provide
for expansion of steam already admitted to the cylinders
and to give lead or cushioning by letting the steam in
about 0.8 inch (3 mm) from the end of the stroke to begin the
reciprocating motion again. The valve gear also provided for
reversing by admitting steam to the opposite side of the piston.
Long-lap or
long-travel valves gave wide-open ports for the exhaust
even when early cut-îff was used, whereas with short travel
at early cut-off, exhaust and emission openings became smaller
so that at speeds of over 60 mph (96 kph) one-third of the
ehergy of the steam was expanded just getting in and out of the
cylinder. This elementary fact was not universal1y
accepted until
about 1925 because it was felt that too much extra
wear would occur with long-travel valve layouts.
Valvå operation on most early British locomotives was
by Stephenson link motion, dependent on two eccentrics on
the driving àõ1å connected by rods to the top and bottom
of an expansion link. À block in the link, connected to the
reversing lever under the control of the driver, imparted the reciprocating
motion tî the valve spindle. With the block at the top
of the link, the engine would be in full forward gear and
steam would be admitted to the cylinder for perhaps 75% of
the stoke. As the engine was notched up by moving the
lever back over its serrations (like the handbrake lever of à
ñàr), the cut-off was shortened; in mid-gear there was no steam
admission to the cylinder and with the block at the bottom
of the link the engine was in full reverse.
Walschaert's valvegear, invented in 1844 and
in general use after 1890, allowed more precise adjustment
and easier operation for the driver. An eccentric rod worked from à
return crank by the driving axle operated the expansion link;
the block imparted the movement to the valve spindle, but
the movement was modified by à combination lever from à crosshead
on the piston rod.
Steam was collected as dry as possible along the top
of the boiler in à perforated pipe, or from à point above the
boiler in à dome, and passed to à regulator which controlled
its distribution. The most spectacular development of
steam locomotives for heavy haulage and high speed runs was
the introduction of superheating. À return tube, taking
the steam back towards the firebox and forward again to à
header at the front end of the boiler through an enlarged
flue-tube, was invented by Wilhelm Schmidt of Cassel, and
modified by other designers. The first use of such equipment in
Britain was in 1906 and immediately the savings in fuel and especially water
were remarkable. Steam at 175 psi, for example, was generated 'saturated'
at 371'F (188'Ñ); by adding 200'F (93'C) of superheat, the steam expanded much
more readily in the cylinders, so that twentieth-century
locomotives were able to work at high speeds at cut-offs as
short as 15%. Steel tyres, glass fibre boiler lagging, long-lap piston
valves, direct steam passage and superheating all contributed to the
last
phase of steam
locomotive performance.
Steam from the boiler was also for other purposes.
Steam sanding was
introduced for traction in 1887 on th
Midland Railway,
to improve adhesion better than gravity
sanding, which
often blew away. Continuous brakes were
operated by à
vacuum created on the engine or by ñîmpressed air supplied by à steam pump. Steam
heat was piped to the carriages, arid steam dynamos [generators]
provided electric light.
Steam locomotives are classified according to the
number of wheels. Except for small engines used in
marshalling óàrds, all modern steam locomotives had leading
wheels on a pivoted bogie or truck to help guide them around
ñurves. The trailing wheels helped carry the weight of the
firebox. For many years the 'American standard' locomotive was
a 4-4-0, having four leading wheels, four driving wheels
and no trailing wheels. The famous Civil War locomotive, the General, was à 4-4-0,
as was the New York Central Engine No
999, which set à speed record
î1 112.5 mph (181 kph) in 1893. Later, à common freight locomotive
configuration was the Mikado type, à 2-8-2.
À Continental classification counts axles instead îf
wheels, and another modification gives drive wheels à letter
of the alphabet, so the 2-8-2 would be 1-4-1 in France and
IDI in Germany.
The largest steam locomotives were articulated, with
two sets of drive wheels and cylinders using à common
boiler. The sets îf drive wheels were separated by à pivot;
otherwise such à large engine could not have negotiated curves.
The largest ever built was the Union Pacific Big Âoó,
à 4-8-8-4, used to haul freight in the mountains of the western
United States. Even though it was articulated it could not
run on sharp curves. It weighed nearly 600 tons, compared to
less than five tons for Stephenson's Rocket.
Steam engines could take à lot of hard use, but they
are now obsolete, replaced by electric and especially
diesel-electric locomotives. Because of heat losses and
incomplete combustion of fuel, their thermal efficiåncó was rarely
more than 6%.
Diesel locomotives
Diesel locomotives are most commonly diesel-electric. À
diesel engine drives à dynamo [generator] which provides
power for electric motors which turn the
drive wheels,
usually through à pinion gear driving à ring gear on
the axle. The first diesel-electric propelled rail car was
built in 1913, and after World War 2 they replaced steam
engines completely, except where electrification of railways is
economical.
Diesel locomotives have several advantages over steam engines.
They are instantly ready for service, and can be shut down
completely for short ðeriods, whereas it takes some time to
heat the water in the steam engine, especially in cold weather,
and the fire must be kept up while the steam engine is on
standby. The diesel can go further without servicing, as it
consumes nî water; its thermal efficiency is four times as high,
which means further savings of fuel. Acceleration and
high-speed running
are smoother with à diesel, which means less wear on rails and roadbed. The economic
reasons for turning to diesels were overwhelming after the war,
especially in North America, where the railways were in direct competition
with road haulage over very long distances.
Electric traction
The first electric-powered rail car was built
in 1834, but early electric cars were battery powered, and the
batteries were heavy and required frequent recharging. Òîdàó å1åñtriñ trains
are not self-contained, which means that they get their power from overhead
wires or from à third rail. The power for the traction motors
is collected from the third rail
by means of à shoe
or from the overhead wires by à pantograph.
Electric trains are the most åñînomical to operate,
provided that
traffic is heavy enough to repay electrification of the
railway. Where trains run less frecuentló over long distances
the cost of electrification is prohibitive. DC systems
have been used as opposed to ÀÑ because lighter traction
motors can be used, but this requires power substations
with rectifiers to convert the power to DÑ from the ÀÑ
of the commercial mains. (High voltage DC power is difficult
to transmit over long distances.) The latest development
of electric trains
has been the installation of rectifiers in the cars themselves
and the use of the same ÀÑ frequency
as the commercial mains (50 Hz in
Europe, 60 Hz in North America),which means that fewer substations
are necessary.
Railway systems
The foundation of à modern railway system is track
which does not deteriorate under stress of traffic. Standard
track in Britain comprises a flat-bottom section of rail
weighing 110 lb
per yard (54 kg per metre)
carried on 2112 cross-sleepers per
mile (1312 per km). Originally
creosote-impregnated wood sleepers [cross-ties] were used, but they are
now made of post-stressed concrete. This enables the rail to
transmit the
pressure, perhaps
as much as 20 tons/in2(3150 kg/cm2) fromthe small area of contact with the
wheel, to the ground below the track formation
where it is reduced through the sole
plate and the sleeper to about
400 psi (28 kg/cm2). In soft ground, thick polyethylene sheets are generally
placed under the ballast to prevent pumping of slurry under
the weight of trains.
The rails are tilted towards one another on à 1 in 20
slîðå. Steel rails tnay last 15 or 20 years in traffic, but
to prolong the undisturbed life of track still longer,
experiments have been carried out with paved concrete track (PACÒ)
laid by à slip paver similar to concrete highway construction
in reinforced concrete. The foundations, if new, are similar
to those for à
motorway. If on
the other'hand, existing railway formation is to be
used, the old ballast is såà1åd with à bitumen emulsion before
applying the concrete which carries the track fastenings glued
in with cement grout or epoxy resin. The track is made
resilient by use of rubber-bonded cork packings 0.4
inch (10 mm) thick. British Railways purchases rails in 60 ft
(18.3 m) lengths which are shop-welded into 600 ft (183 m)
lengths and then welded on site into continuous welded
track with pressure-relief points at intervals of several
miles. The contfnuotls welded rails make for à
steadier and less
noisy ride for the passenger and reduce the tractive
effort.
Signalling
The second important factor contributing to safe rail travel
is the system of signalling. Originally railways relied on the time
interval to ensure the safety of a succession
of trains, but the defects
rapidly manifested themselves, and a space interval, or the block system, was
adopted, although it was not enforced legally on British passenger
lines until the
Regulation of
Railways Act of 1889. Semaphore signals
became universally
adopted on running lines and the interlocking îf
points [switches] and signals (usually accomplished mechanically by
tappets) to prevent conflicting movements being signalled was also
à requirement of the 1889 Àñt. Lock-and-block signalling, which ensured à
safe sequence of movements by electric checks, was introduced on the
London, Chatham and Dover Railway in 1875.
Track circuiting, by which the presence of à train is detected
by an electric current passing from one rail to another through the
wheels and axles, dates from 1870 when William Robinson applied
it in the United States. In England
the Great Eastern Railway
introduced power operation of points and signals at Spitaifields goods yard
in 1899, and three years later track-circuit operation of powered
signals was in operation on 30 miles (48 km) of the London
and Sout Western Railway main line.
Day colour light signals, controlled automatically by
the trains through track circuits, were installed on the
Liverpool Overhead Railway in 1920 and four-aspect day colour
lights (red, yellow, double yellow and green) were provided
on Southern Railway routes from 1926 onwards. These
enable drivers of high-speed trains to have à warning two
block sections ahead of à possible need to stop. With track circuiting
it became usual to show the presence îf vehicles on à track
diagram in the signal cabin which allowed routes to be controlled
remotely by means of electric relays. Today, panel
operation of
considerable stretches of railway is common-ðlàñå; at Rugby, for instance, à
signalman can control the points at à station 44 miles (71 km) away, and
the signalbox at London Bridge controls movements on the
busiest 150 track-miles of British Rail. By the end of the I980s,
the 1500 miles (241Î km) of the Southern Region of British Rail
are to be controlled from 13 signalboxes. In modern panel
installations the trains are not only shown on the track
diagram as they move from one section to another, but the train identification
number appears electronically in each section. Ñîmputer-assisted
train description, automatic train råporting and, at stations such as London
Bridge, operation of platform indicators, is now usual.
Whether points are operated manually or by an electric point
motor, they have to be prevented from moving while a train
is passing over them and facing points have to be locked,
ànd ðroved tî Üå lîñkåd (îr 'detected' ) before thå relevant
signal can permit à train movement. The blades of the
points have to be closed accurately (Î.16 inch or 0.4 cm is the
maximum tolerance) so as to avert any possibility of à wheel
flange splitting the point and leading to à derailment.
Other signalling developments of recent years include
completely automatic operation of simple point layouts, such as the
double crossover at the Bank terminus of the British Rails's
Waterloo and City underground railway. On London Òransport's
underground system à plastic roll operates junctions
according to the timetable by means of coded punched
holes, and on the Victoria Line trains are operated automatically
once the driver has pressed two buttons to indicate
his readiness to start. Íå also acts as the guard, controlling
the opening îf thå doors, closed circuit television giving
him à view along the train. The trains are controlled (for
acceleration and braking) by coded impulses transmitted through
the running rails to induction coils mounted on the front
of the train. The absence of code impulses cuts off the current
and applies the brakes; driving and speed control is covered
by command spots in which à frequency of 100 Hz corresponds
to one mile per hour (1.6 km/h), and l5 kHz
shuts off the
current. Brake applications are so controlled that
trains stop smoothly and with great accuracy at the desired place on platforms.
Occupation of the track circuit ahead by à train automatically stops the
following train, which cannot receive à code.
On Âritish main lines an automatic warning system is being
installed by which the driver receives in his ñàb à visual and audible warning
of passing à distant signal at caution; if he does not acknowledge the warning
the brakes are applied automatically. This is accomplished by magnetic
induction between à magnetic unit placed in the track and actuated according to
the signal aspect, and à unit on the train.
Train control
In England train control began in l909 on the Midland
Railway, particularly to expedite the movement îf coal trains and to see that
guards and enginemen were
relieved at the
end of their shift and were not called upon to work excessive overtime.
Comprehensive train control systems, depending on complete diagrams of
the track layout and records of the position of engines,
crews and rolling stock, were developed for the whole of Britain, the Southern
Railway being the last to adopt it during World War 2, having hitherto given à
great deal of responsibility to signalmen for the regulation of trains.
Refinements îf control include advance traffic information(ATI)
in which information is passed from yard to yard by telex
giving types of wagon, wagon number, route code, particulars îf the load,
destination
station and
consignee. In l972 British Rail decided to
adopt à
computerized freight information and traffic control system known as TOPS
(total operations processing system) which was developed over eight years by
the Southern Pacific company in the USA.
Although à great deal of rail 1ràffiñ in Britain is
handled by block trains from point of origin to destination, about onefifth of the
originating tonnage is less than a train-load. This means that wagons must be sorted on their journey. In
Britain there are about 600 terminal points on a 12,000 mile network whitch is
served by over 2500 freight trains made up of varying assortments of 249,000 wagons and 3972 locomotives, of witch 333 are electric. This
requires the speed of calculation and the information storage and
classification capacity of the modern computer, whitch has to be linked to
points dealing with or generating traffic troughout the system.The computer
input, witch is by punched cards, covers details of loading or unloading of
wagons and their movements in trains, the composition of trains and their
departures from and arrivals at yards ,and the whereabouts of locomotives. The
computer output includes information on the balanse of locomotives at depots
and yards, with particulars of when maintenanse examinations are due, the
numbers of empty and loaded wagons, with aggregate weight and brake forse, and
wheder their movement is on time, the location of empty wagons and a forecast
of those that will become available, and the numbers of trains at any location,
with collective train weigts and individual details of the component wagons.
A closer check on what
is happening troughoud the
system is thus provided,
with the position of consignments in transit, delays in movement, delays in
unloading wagons by customers, and the capasity of the system to handle future
traffic among the information readily available. The computer has a built-in
self-check on wrong input information.
Freight handling
The merry-go-round
system enables coal for power
stations to be loaded into
hopper wagons at a colliery
without the train being
stopped, and at the power station the train is hauled round a loop at less than
2mph (3.2 km/h), a trigger devise automatically unloading the wagons without the train being stopped. The
arrangements also provide for automatic weighing of the
loads. Other bulk loads can be dealt with in the same way.
Bulk powders, including cement, can be loaded and
discharged pneumatically, using either rài1 wagons or containers. Iron
ore is carried in 100 ton gross wagons (72 tons of payload)
whose coupling gear is designed to swivel, so that wagons
can be turned upside down for discharge without uncoupling
from their train. Special vans take palletized loads
of miscellaneous merchandise or such products as fertilizer,
the van doors being designed so that all parts of the interior
can be reached by à fork-lift truck.
British railway companies began building their stocks
of containers in 1927, and by 1950 they had the largest
stock of large containers in Western Europe. In 1962 British
Rail decided to use International Standards Organisation
sizes, 8 ft (2,4 m) wide by 8 ft high and 1Î, 20, 30 and 40
ft (3.1, 6.1, 9.2 and 12.2 m) long. The 'Freightliner'
service of container trains uses 62.5 ft (19.1 m) flat wagons with
air-operated disc brakes in sets îf five and was inaugurated in
1965. At depots
'Drott'
pneumatic-tyred cranes were at first provided but rail-mounted
Goliath cranes are now provided.
Cars are handled by double-tier wagons. The British
car industry is à big user of 'ñomðànó'
trains, which are operated for à single customer. Both Ford and Chrysler
use them to exchange parts between specialist factories ànd the
railway thus becomes an extension of factory transport.
Company trains frequent1ó consist of wagons owned by the
trader; there are about 20,000 on British railways, the oil
industry, for example, providing most îf the tanks it needs to
carry 21 million tons of petroleum products by rail each year
despite
competition from
pipelines.
Gravel dredged from the shallow seas is another
developing source of rail traffic. It is moved in 76 ton lots by 100 ton gross
hopper wagons and is either discharged on to belt conveyers
to go into the storage bins at the destination or, in another system, it is
unloaded by truck-mounted discharging machines.
Cryogenic (very low temperature) products are also
transported by rail in high capacity insulated wagons. Such products include
liquid oxygen and liquid nitrogen which are taken
from à central plant to strategically-placed railheads where
the liquefied gas is transferred to road tankers for the journey
to its ultimate destination.
Switchyards
Groups of sorting sidings, in which wagons [freight
cars] can be arranged in order sî that they can be
detached from the
train at their destination with the least possible delay, are
called marshalling yards in Britain and classification yards or
switchyards in North America. The
work is done by small locomotives
called switchers or shunters, which move 'cuts' of trains from one
siding to another until the desired order is achieved.
As railways became more complicated in their system
layouts in the
nineteenth century, the scope and volume of necessary
sorting became greater, and means of reducing the time
and labour involved were sought. (Âó 1930, for every 100 miles
that freight trains were run in Britain there were 75 miles
of shunting.) The sorting of coal wagons for return to the
collieries had been assisted by gravity as early as 1859, in the
sidings at Tyne dock on the North Eastern Railway; in 1873
the London & North Western Railway sorted traffic to and
from Liverpool on the Edge Hill 'grid irons': groups of
sidings laid out
on the slope of à hill where gravity provided the
motive power, the steepest gradient being 1 in 60 (one foot of
elevation in sixty feet of siding). Chain drags were used
for braking he wagons. À shunter uncoupled the wagons in
'cuts' for the various destinations and each cut was turned
into the appropriate siding. Some gravity yards relied
on à code of whistles to advise the signalman what 'road'
(siding) was required.
In the late nineteenth century the hump yard was
introduced to provide gravity where there was nî natural slope of the
land. In this the trains were pushed up an artificial mound with
à gradient of perhaps 1 in 80 and the cuts
were 'humped' down à somewhat steeper gradient on the other
side. The separate cuts would roll down the selected siding in
the fan or 'balloon' of sidings, which would ånd in à slight
upward slope to assist in the stopping of the wagons. The
main means of stopping the wagons, however, were railwaymen
called shunters who had to run alongside the wagons and apply
the brakes at the right time. This was dangerous and
required excessive manpower.
Such yards àððåàråd all over North America and
north-east England and began to be adopted elsewhere in England. Much
ingenuity was devoted to means of stopping the wagons;
à German firm, Frohlich, came up with à hydraulically operated
retarder which clasped the wheel of the wagon as it
went past, to slow it down to the amount the operator throught
nåñåssaró.
An entirely new concept came with Whitemoor yard at
March, near
Cambridge, opened by the London & North
Eastern Railway in
l929 to concentrate traffic to and from East Anglian
destinations. When trains arrived in one of ten reception
sidings à shunter examined the wagon labels and prepared
à 'cut card' showing how the train should be sorted
into sidings. This was sent to the control tower by pneumatic
tube; there the points [switches] for the forty sorted
sidings were preset in accordance with the cut card; information
for several trains could be stored in à simple pin and
drum device.
The hump was approached by à grade of 1 in 80. On the
far side was à short stretch of 1 in 18 to accelerate the
wagons, followed by 70 yards {64 m) at 1 in 60 where the
tracks divided into four, each equipped with à Frohlich
retarder. Then the four tracks spread out to four balloons of ten
tracks each, comprising 95 yards (87 m) of level track
followed by 233 yards (213 m) falling at 1 in 200, with the remaining 380 yards
(348 m) level. The
points were moved in the predetermined sequence by track
circuits actuated by the wagons, but the operators had to estimate the effects
on wagon speed of the retarders, depending to à degree on whether the retarders
were grease or oil lubricated.
Pushed by an 0-8-0 small-wheeled shunting engine at
1.5 to 2 mph (2.5 to 3 km/h), à train of 70 wagons could be sorted in seven
minutes. The yard had à throughput of about 4000 wagons à day. The sorting
sidings were allocated: number one for Bury St Edmunds, two for Ipswich, and sî
forth. Number 31 was for wagons with tyre fastenings which
might be ripped off by retarders, which were not used on that
siding. Sidings 32 tî 40 were for traffic to be dropped at
wayside stations; for these sidings there was an additional
hump for sorting these wagons in station order. Apart from the
sorting
sidings, there
were an engine road, à brake van road, à
'cripple' road for
wagons needing repair, and transfer road to three
sidings serving à tranship shed, where small shipments not
filling entire wagons could be sorted.
British Rail built à series of yards at strategic
points; the yards usually had two stages of retarders, latterly
electropneumatically operated, to control wagon speed. In lateryards electronic
equipment was used to measure the weight of each wagon and
estimate its
rolling
resistance. By feeding this information into à computer, à suitable
speed for the wagon could be determined and the retarder
operatedautomatically to give the desired amount of braking. These predictions
did not always prove reliable.
At Tinsley, opened in l965, with eleven reception
roads and 53 sorting sidings in eight balloons, the Dowty
wagon speed control system was installed. The Dowty system
uses many small units (20,000 at Tinsley) comprising
hydraulic rams on the inside of the rail, less than à wagon
length apart. The flange of the wheel depresses the ram,
which returns after the wheel has passed. À speed-sensing
device determines whether the wagon is moving too fast from thehump; if the
speed is too fast the ram automatically has à retarding
action.
Certain of the
units are booster-retarders; if the wagon is moving too slowly, à hydraulic
supply enablesthe ram to accelerate the wagon. There are 25 secondary sorting
sidings at Tinsley
to which wagons are sent over à
secondary hump by
the booster-retarders. If individual unitsfail the rams can be replaced.
An automatic telephone exchange links àll the traffic
and administrative offices in the yard with the railway
controlîffiñå, Sheffield Midland Station and the local steelworks(principal
source of traffic). Two-wàó loudspeaker systems are
available through all the principal points in the yard, and radio
telephone equipment is used tî speak to enginemen. Fitters
maintaining the retarders have walkiå-talkie equipment.
The information
from shunters about the cuts and how many wagons in each, together with
destination, is
conveyed by
special data transmission equipment, à punched tape
being produced to feed into the point control system for
each train over the hump.
As British Railways have departed from the wagon-load system
there is less employment for marshalling yards. Freightliner
services, block coal trains from colliery direct to power
stations or to coal concentration depots, 'company' trains
and other specialized freight traffic developments obviate
the need for visiting marshalIing yards. Other factors
are competition from motor transport, closing of wayside
freight depots and of many small coal yards.
Modern passenger service
In Britain à network of city tocity services
operates at speeds of up to 100 mph (161 km/h) and at
regular hourly intervals, or 30 minute intervals on such
routes as London to Birmingham. On some lines the speed
is soon to be raised to 125 mph (201 km/h)with high speed
diesel trains whoså prototype has been shown to be
capable of 143 mph
(230 km h). With the advanced passenger train (APT) now under
development, speeds of 150 mph (241 km/h) are envisaged. The Italians are
developing à system capable of speeds approaching 200 mph
(320 km/h) while the Japanese and the French already operate
passenger trains at speeds of about
150mph (241 km/h).
The APT will be powered either by electric motors or
by gas turbines, and it can use existing track because of
its pendulum suspension which enables it to heel over when travelling
round curves. With stock hauled by à conventional locomotive,
the London to Glasgow electric service holds the
European record for frequency speed over à long distance.
When the APT is in service, it is expected that the London
to Glasgow journey time of five hours will be reduced
to 2.5 hours.
In Europe à number of combined activities organized
through the
International Union af Railways included the
Trans-Europe-Express
(TEE) network of high-speed passenger trains, à similar freight service,
and à network of railway-àssociated road services marketed as
Europabus.
Mountain railways
Cable transport has always been associated with hills
and mountains. In the late 1700s and early 1800s the
wagonways used for moving coal from mines to river or sea ports
were hauled by cable up and down inclined tracks.
Stationary steam engines built near the top of the incline drove
the cables, which were passed around à drum connected to
the steam engine and were carried on rollers along the
track. Sometimes cable-worked wagonways were self-acting if loaded
wagons worked downhill, fîr they could pull up the lighter
empty wagons. Even after George Stephenson perfected
the travelling steam locomotive to work the early passenger
railways of the 1820s and 1830s cable haulage was sometimes
used to help trains climb the steeper gradients, and
cable working continued to be used for many steeply-graded industrial wagonways
throughout the 1800s. Today à few cable-worked inclines survive at
industrial sites and for such unique forms of transport as the San
Francisco tramway [streetcar] system.
Funiculars
The first true mountain railways using steam
locomotives
running on à railway track equipped for rack and pinion
(cogwheel) propulsion were built up Mount Washington, USA, in 1869 and Mount
Rigi, Switzerland, in 1871. The latter was the pioneer of what today has
become the most extensive mountain transport system in the
world. Much of Switzerland consists of high mountains, some
exceeding l4,000 ft (4250 m). From this development in mountain transport
other methods were developed and in the following 20 years until the turn of
the century funicular railways were built up à number of mountain slopes.
Most worked on à similar principle to the cliff lift, with
two cars connected by cable balancing each other. Because of the
length of some
lines, one mile
(1.6 km) or more in à few cases, usually only à single track is provided over
most of the route, but a short length of double track is laid down at the
halfway point where the cars cross each other. The switching of cars through
the double-track section is achieved automatically by using double-flanged wheels on one side of
each ñar and flangeless wheels on the other so that one car is always guided
through the righthand track and the other through the left-hand track. Small gaps are left in
the switch rails to allow the cable tî pass through without impeding the wheels.
Funiculars vary in steepness according to location and may
have gentle curves; some are not steeper than 1 in 10 (10per
cent), others reach à maximum steepness of 88 per cent.On the
less steep lines the cars are little different from, but smaller
than, ordinary railway carriages. On the steeper lines the cars have à
number of separate compartments, stepped up one from another so
that while floors and seats are level a compartment at the
higher end may be I0 or even 15 ft (3 or
4 m) higher than the lowest
compartment at the other end. Some of the bigger cars seat 100 passengers,
but most carry
fewer than this.
Braking and safety are of vital importance on steep
mountain lines to prevent breakaways. Cables are regularly
inspected and renewed as necessary but just in case the cable
breaks a number of braking systems are provided to stop the car quickly.
On the steepest lines ordinary wheel brakes would not
have any effect and powerful spring-loaded grippers on the ñàr
underframe act on the rails as soon as the cable becomes
slack. When à cable is due for renewal the opportunity is
taken to test the braking system by cutting
the cable
ànd checking
whether the cars stop within the prescribed
distance. This
operation is done without passengers
The capacity of funicular railways is limited to the two cars,
which normally do not travel at mîrå than about 5 to 1Î mph (8 to 16
km/h). Some lines are divided 1ntî sections
with pairs îf cars covering
shorter lengths.
Rack railways
The rack and pinion system principle dates
from the
pioneering days of the steam locomotive between
1812 and 1820
which coincided with the introduction of
iron rails. 0ne
engineer, Blenkinsop, did not think that
iron wheels on
locomotives would have sufficient grip on
iron rails, and on
the wagonway serving Middleton colliery near Leeds he laid an
extra toothed rail alongside one of the ordinary rails, which
engaged with à cogwheel on the locomotive. The Middleton line was relatively
level and it was soon found that on railways with only
gentle climbs the rack system was not needed. If there was
enough weight on the locomotive driving wheels they would grip
the rails by friction. Little more was heard of rack
railways until the 1860s, when they began to be developed for
mountain railways in the USA and Switzerland.
The rack system for the last 100 years has used an
additional centre toothed rail which meshes with cogwheels under locomotives
and coaches. There are four basic types of rack varying
in details: the Riggenbach type looks like à steel ladder,
and the Abt and Strub types use à vertical rail with teeth
machined out of the top. 0ne or other of these systems
is used on most rack lines but they are safe only on gradients
nî steeper than 1 in 4 (25 per cent). One line in Switzerland
up Mount Pilatus has à gradient of 1 in 2 (48 per cent)
and uses the Locher rack with teeth cut on both sides of the
rack rail instead of on top, engaging with pairs of
horizontally-mounted
cogwheels on each side, drivihg and
braking the railcars.
The first steam locomotives for steep mountain lines
had vertical boilers but later locomotives had
boilers mounted at an angle to the main frame so that they were
virtually horizontal when on the climb. Today steam locomotives
have all but disappeared from most mountain lines ànd
survive in regular service on only one line in Switzerland, on
Britain's only rack line up Snowdon in North Wales, and à
handful of others. Most of the remainder have been electrified or
à few converted to diesel.
Trams and trolleybuses
The early railways used in mines with four-wheel
trucks and wooden beams for rails were known as tramways. From
this came the word tram for à four-wheel rail vehicle. The world's
first street rài1wàó, or tramway, was built in New York
in 1832; it was à mile (1,6 km) long and known as the New
York & Harlem Railroad. There were two horse-drawn ñàrs,
each holding 30 people. The one mile route had grown to four
miles (6.4 km) by 1834, and cars were running every 15
minutes; the tramway idea spread quickly and in the 1880s there
were more than 18,000 horse trams in the USA and over
3000 miles (4830 km) of track. The building îf tramways, or
streetcar systems, required the letting of construction contracts
and the acquisition of right-of-way easemerits, and was an
area of political patronage and corruption in many citó
governments.
The advantage
of the horse tram over the horse bus was that steel wheels on
steel rails gave à smoother ride and less friction. À horse could
haul on rails twice as much weight
às on à roadway.
Furthermore, the trams had brakes, but buses still relied on
the weight of the horses to stop the
vehicle. The American example was
followed in Europe and the first tramway in Paris was opened in 1853
appropriately styled 'the American Railway'. The first line
in Britain was opened in Birkenhead in 1860. It was built by
George Francis
Train, an
American, who also built three short tramways in London
in 1861: the first îf these ràn from Ìàrblå Arch for à short
distance along the Bayswater Road. The lines used à type of
step rail which stood up from the road surface and interfered
with other traffic, so they were taken up within à year.
London's more permanent tramways began running in 1870,
but Liverpool had à 1inå working in November 1869. Rails
which could be laid flush with the road surface were used
for these lines.
À steam tram was tried out in Cincinatti, Ohio in 1859
and in London in 1873; the steam tram was not widely
successful because tracks built for horse trams could not stand
up tî thå weight of à locomotive.
The solution to this problem was found in the cable
ñàr. Cables, driven by powerful stationary steam engines at
the end of the route, were run in conduits below the
roadway, with an attachment passing down from the tram through
à slot in the roadway to grip the cable, and the car
itself weighed nî more than à horse car. The most famous application
of cables to tramcar haulage was Andrew S Hallidie's 1873
system on the hills of San Francisco — still in use and
à great tourist attraction today. This was followed by others
in United States cities, and by 1890 there were some 500
miles (805 km) of cable tramway in the USA. In London there
were only two cable-operated lines — up Highgate Hill from
1884 (the first in Europe) and up the hill between Streatham
and Kennington. In Edinburgh, however, there was an
extensive cable system, as there was in Melbourne.
The ideal source of power for tramways was
electricity, clean and flexible but difficult at first to
apply. Batteries were far too heavy; à converted horse ñàr with
batteries under the seats and à single electric motor was tried in
London in 1883, but the experiment lasted only one day.
Compressed air driven trams, the invention of Ìàjîr Beaumont,
had been tried out between Stratford and Leytonstone in 1881; between
1883 and 1888 tramcars hauled by battery locomotives ran on
the same route. There was even à coal-gas driven tram with
an Otto-type gas engine tried in Croydon in 1894.
There were early experiments, especially in the USA
and Germany, to enable electricity from à power station to
be fed to à tramcar in motion. The first useful system
emp1îóåd à small two-wheel carriage running on top of an overhead
wire and connected tî the tramcar by à cable. The circuit
was completed via wheels and the running rails. À tram route
on this system was working in Montgomery, Alabama, as early
as 1886. The cohverted horse cars had à motor mounted on one of the end
platforms with chain drive to one axle. Shortly afterwards, in the USA and
Germany there werå trials on à similar principle but using à four-wheel
overhead carriage known as à troller, from which the modern word trolley is
derived.
Real surcess came when Frank J Sprague left the US
Navy in 1883 to devote more time to problems of using electricity for power.
His first important task was to equip the Union Passenger Railway at Richmond,
Virginia, for ålectrical working. There he perfected the swivel trolley ðî1å
which could run under the overhead wire instead of above it. From this success
in 1888 sprang all the subsequent tramways of the world; by 1902 there were
nearly 22,000 miles (35,000 km) of
Ålåñtrified
tramways in the USA alone. In Great Britain there were electric trams in
Manchester from 1890 and London's first electric line was opened in 1901.
Except in Great Britain and countries under British
influence,
tramcars were normally single-decked. Early
electric trams had
four wheels and the two axles were quite close together so that
the car could take sharp bends. Eventually, as the need grew for larger cars,
two bogies, or trucks, were used, one under each end of the car.
Single-deck cars of this type were often coupled together with
à single driver and one or two conductors, Double-deck cars
could haul trailers in peak hours and for à time such
trailers were à common sight in London.
The two main power collection systems were from
overhead wires, as
already described — though modern
tramways often use
à pantograph collecting deviñå held by springs against the
underside of the wire instead of the
traditional trolley — and the
conduit system. This system is derived from the slot in the street used for
the early cablecars, but instead of à moving cable there are current supply rails
in the conduit. The tram is fitted with à device called à plough
which passes down into the conduit. On each side of the
plough is à contact shoe, one of which presses against each of
the rails. Such à system was used in inner London, in New
York and Washington DC, and in European cities.
Trams were driven through à controller on each
platform. In à single-motor car, this allowed power to pass
through à resistariceas well as the motor, the amount îf
resistancå being reduced in steps by moving à handle as
desired, to feed more power to the motor. In two-motor cars à much
more economical ñîntrol was used. When starting, the two
motors were ñînnåctåd in series, so that each motor received power
in turn — in effect, each got half thå power available,
the amount of power again being regulated bó resistances. As
speed rose
the controller was
'notched up' to à further set of steps in which the motors were
connected in parallel so that each
råñeived current direct from the
power source instead o sharing it. The ñîntrîllår could also be moved to à
further set of notches which gave degrees of å1åñtrical
braking, achieved by connecting the motors so that they acted
as generators, the power generated being absorbed by the resistances. Àn
Àmerican tramcar revival in the I930s resulted in the design
of à new tramcar known as the ÐÑÑ
type after the Electric Railway
Presidents Ñînfårånce Committee which commissioned it. These cars,
of which many hundreds were built, had more refined controllers with
more steps, giving smoother acceleration.
The decline of the tram springs from the fact that
while à tram route is fixed, à bus route can be changed as
the need for it changes. The inability of à tram to draw in to
the kerb to discharge and take on passengers was à handicap
when road traffic increased. The tram has continued to hold its
own in some cities, especially, in Europe; its character,
however, is changing and tramways are becoming light rapid transit railways,
often diving underground in the centres of cities. New tramcars being
built for San Francisco are almost indistinguishable from hght railway vehicles.
The lack of flexibility of the tram led to experiments
to dispense with rails altogether and to the trolleybus, îr trackless
tram. The first crude versions were tried out in Germany and the USA in
the early 1880s. The current ñîllection system needed two cables and collector
arms, sine there were nî rails. À short line was tried just outside
Paris in 1900 and an even shorter one — 800 feet (240 m) —
opened in Scranton, Pennsylvania, in l903. In England,
trolleybuses were operating in Bradford and Leeds in 1911 and other
cities
soon followed
their example. America and Canada widely
changed to
trolleybuses in the early l920s and many cities had them. The
trolleybuses tended to look, except for their
mllector arms, like contemporary
motor buses. London’s first trolleybus, introduced in 1931, was
based on à six-wheel bus chassis with an electric motor substituted
for the engine. The London trolleybus fleet, which in 1952 numbered
over 1800, was for some years the largest in the world, and
was composed almost entirely of six-wheel double-deck
vehicles.
The typical trolleybus was operated by means of à pedal-operated
master control, spring-loaded to the 'off' position, and a
reversing lever. Some braking was provided by the electric motor
controls, but mechanical brakes were relied upon
for safety. The same lack of flexibility which had ñîndemned
trams in most parts îf the world also condemned thetrolIeybus.
They were tied as firmly to the overhead wires as were the trams
to the rails.
Monorail systems
Monorails are railways with only one rail instead îf
two. They have been experimentally built for more than à hundred years;
there would seem to be an advantage in that one rail and its
sleepers [cross-ties] would occupy less space than two,
but in practice monorail construction tended to be complicated
on account of the necessity of keeping the cars upright.
There is also the problem of switching the cars from one
line to another.
The first monorails used an elevated rail with the
cars hanging down on both sides, like pannier bags [saddle
bags] on à pony or à bicycle. À monorail was patented in
1821 by Henry Robinson Palmer, engineer to the London Dock Company,
and the first line was built in 1824 to run between the
Royal Victualling Yard and the Thames. The elevated wooden
rail was à plank on edge bridging strong wooden supports,
into which it was set, with an iron bar on top to take
the wear from the double-flanged wheels of the cars. À similar
line was built to carry bricks to River Lea barges from à
brickworks at Cheshunt in 1825. The cars, pulled by à horse and
à tow rîðå, were in two parts, one on each side of the rail,
hanging from a framework which carried the wheels.
Later, monorails on this principle were built by à
Frenchman, Ñ F M T Lartigue. Íå put his single rail on top of à series
of triangular trestles with their bases on the ground; he also
put à guide rail on each side of the trestles on which ran
horizontal wheels attached to the cars. The cars thus had both
vertical and sideways support ànd were suitable for higher
speeds than the earlier type.
À steam-operated line on this principle was built in
Syria in 1869 by J L Hadden. The locomotive had two vertical boilers,
înå on each side îf the pannier-type vehicle.
An electric Lartigue line was opened in central France
in 1894, and there were proposals to build à network of
them on Long Island in the USA, radiating from Brooklyn.
There was à demonstration in London in 1886 on à short line,
trains being hauled by à two-boiler Mallet steam locomotive.
This had two double-flanged driving wheels running on the
raised centre rail and guiding wheels running on tracks on
each side of the trestle. Trains were switched from one track
to anothe
by moving à whole
section of track sideways to line up with another section. In 1888 à line on this
principle was laid in Ireland from Listowel to Âàllybunion, à
distance of 9,5 miles; it ran until 1924. There were three
locomotives, each with two horizontal boilers hanging one each side of
the centre wheels. They were capable of 27 mph (43.5 km/h); the carriages
wårå built with the lower parts in two sections, between which were the
wheels.
The Lartigue design was adapted further by F B Behr,
who built à three-milå electric line near Brussels in
l897. The mînîrài1 itself was again at the top of àn 'À' shaped
trestle, but there were two balancing and guiding rails on each
side, sî that although the weight of the ñàr was carried by
one rail, therå were really five rails in àll. The ñàr weighed
55 tons and had two four-wheeled bogies (that is, four wheels in
line în each bogie). It was built in England and had motors
putting
out à total of 600
horsepower. The ñàr ran at 83 mph (134 km/h) and was said to have reached 100 mph
(161 km/h) in private trials. It was extensively tested by
representatives of the Belgian, French and Russian governments, and Behr
came near to success in achieving wide-scale application of
his design.
An attempt to build à monorail with one rail laid on
the ground in order to save space led to the use of à
gyroscope to keep the train upright. À gyroscope is à rapidly
spinning flywheel which resists any attempt to alter the angle
of the axis on which it spins.
À true monorail, running on à single rail, was built
for military purposes by Louis Brennan, an Irishman who also invented
à steerable torpedo. Brennan applied for monorail patents in 1903,
exhibited à large working model in 1907 and à
full-size 22-ton car in 1909 — 10. It was held upright by two gyroscopes,
spinning in opposite directions, and carried 50 people or
ten tons of freight.
À similar ñàr carrying only six passengers and à
driver was demonstrated in Berlin in 1909 by August Scherl, who
had taken out à patent in 1908 and later ñàmå to an
agreement with Brennan to use his patents also. Both systems allowed the
cars to lean over, like bicycles, on curves. Scherl's was an electric
car; Brennan's was powered by an internal combustion engine
rather than steam so as not to show any tell-tale smoke
when used by the military. À steam-driven gyroscopic system
was designed by Peter Schilovsky, à Russian nobleman. This reached only the
model stage; it was held upright by à single steam-driven gyroscope placed in
the tender.
The disadvantage with gyroscopic monorail systems was that
they required power to drive the gyroscope to keep the train
upright even when it was not moving.
Systems were built which ran on single rails on the
ground but used à guide rail at the top to keep the train
upright. Wheels on top of the train engaged with the guiding
rail. The structural support necessary for the guide rail
immediately nullified the economy in land use which was the main argument
in favour of monorails.
The best known such system was designed by Í Í Tunis
and built by
August Belmont. It was 1,2 miles long (2.4 km) and ran
between Barton Station on the New York, New
Haven &
Hartford Railroad and City Island (Marshall's
Corner) in 1,2
minutes. The overhead guide rail was arranged to make
the single car lean over on à curve and the line was designed
for high speeds. It ran for four months in l9I0, but on 17
July îf that year the driver took à curve too slowly, the guidance
system failed and the car crashed with 100 people on
board. It never ran again.
The most successful modern monorails have been the
invention of Dr
Axel L Wenner-Gren, an industrialist born in Sweden. Alweg lines
use à concrete beam carried on concrete supports; the beam can be high in the
air, at ground level or in à tunnel, as required. The cars
straddle the beam, supported by rubber-tyred wheels on top îf the
beam; there are also horizontal wheels in two rows on each side
underneath, bearing on the sides of the beam near the top and bottom
of it. Thus there are five bearing surfaces, as in the Behr
system, but combined to use à single beam instead of à massive
steel trestle framework. The carrying wheels ñîmå up
into the centre line of the cars, suitably enclosed. Electric
current is picked up from power lines at the side
of the beam. À
number of successful lines have been built on the
Alweg system, including à line 8.25 miles (13.3 km) long
between Tokyo and its Haneda airport.
There are several other 'saddle' type systems on the
same principle as the Alweg, including à small industrial
system used on building sites and for agricultural purposes
which can run without à driver. With all these systems,
trains are diverted from one track to another by moving pieces of track
sideways to bring in another piece of track to form à new
link, or by using à flexible section of track to give the same
result.
Other systems
Another monorail system suspends the car beneath
an overhead carrying rail. The wheels must be over the
centre line of the car, so the support connected between
rài1 and car
is to one side, or offset. This allows the rail to be supported
from the other side. Such à system was built between
the towns of Barmen and Elberfeld in Germany in 1898-1901
and was extended in 1903 to à length of 8.2 miles (13
km). It has run successfully ever since, with à remarkable safety
record. Tests in the river valley between the towns showed
that à monorail would be more suitable than à conventional
railway in the restricted space available because monorail cars
could take sharper curves in comfort.
The rail is
suspended on à steel structure, mostly over the River
Wupper itself. The switches or points on the line are in the
form of à switch tongue forming an inclined plane, which
is placed over the rail; the car wheels rise on this plane and are
thus led to the siding.
An experimental line using the same principle of
suspension, but with the ñàr driven by means îf an aircraft
propeller, was designed by George Bennie and built at
Milngavie (Scotland) in 1930. The line was too short for high speeds,
but it was claimed that 200 mph (322 km/h) was possible. There
was an auxiliary rail below the car on which horizontal
wheels ran to control the sway.
À modern system, the SAFEGE developed in France, has
suspended cars but
with the 'rail' in the form of à steel box section
split on the underside to allow the car supports to pass
through it. There are two rails inside the bîõ, one on each
side of the slot, and the cars are actually suspended from four-wheeled
bogies running on the two rails.
Underground railways
The first underground railways were those used in
mines, with small trucks pushed by hand or, later, drawn by
ponies, running on first wooden, then iron, and finally steel
rails. Once the steam railway had arrived, howevår, thoughts
soon turned to building passenger railways under the ground
in cities to avoid the traffic congestion which was
already making itself felt in the streets towards the middle
of the 19th century.
The first underground passenger railway was opened in London
on 1Î January, 1863. This was the Metropolitan Railway, 3.75 miles (6 km) long,
which ran from Paddington to Farringdon Street. Its
broad gauge (7 ft, 2.13 m) trains, supplied by the Great Western Railway, were
soon carrying nearly 27,000 passengers à day. Other
underground lines followed in London, and in Budapest, Berlin,
Glasgow, Paris and later in the rest of Europe, North and
South America, Russia, Japan, China, Spain, Portugal and
Scandinavia, and ðlans and studies for yet more underground
railways have already been turned into reality — îr soon
will be — all over the world. Quite soon every major city able to
dî so will have its underground railway. The reason is the same
as that
which inspired the
Metropolitan Railway over 100
years ago
traffic congestion.
The first
electric tube railway [subway] in the world,the
City and South London, was opened
in 1890 and all subsequent tube railways have been electrically worked.
Subsurface cut-and-cover lines everywhere are also electrically worked.
Thå early locomotives used on undergroundrailways have given way to multiple-unit
trains, with separate motors at various points along the train
driving the wheels, but controlled from à single driving ñàb.
Modern underground railway rolling stock usually has
plenty of standing
space to cater for peak-hour crowds and alarge number of doors,
usually opened and closed by the driver or guard, so that
passengers can enter and leave the trains
quickly at the many, closely
spaced stations. Average underground railway speeds are not high — often
between 20 and 25 mph (32 to 60km/h) including stops, but the trains are usually
much quicker than surface transport in the same area. Where
underground trains emerge into the open on the ådge
of cities, and
stations are à greater distance apart, they
can often attain well over 60 mph
(97 km/h).
The track and ålåñtricitó supply are usually much the
same as that of main-line railways and most underground
lines use forms îf automatic signalling worked by the trains
themselves and similar to that used by orthodox railway systems. The track
curcuit is the basic component of automatic signalling of
this type on àll kinds of railways. Underground railways rely
heavily on automatic signalling because of the close headways, the short
time intervals between trains.
Some railways have nî signals in sight, but the signal 'aspects'
— green, yellow and red — are displayed to the driver in
the ñàÜ of his train. Great advances are being made also with
automatic driving, now in use in à number of cities. Òhe Victoria
Line system in London, the most fully automatic line
now in operation, uses codes in the rails for both safety signalling
and automatic driving, the codes being picked
up by coils on the train and
passed to the driving and monitoring equipment.
Code systems are used on other underground railways but sometimes
they feed information to à central computer, which calculates
where the train should be at any given time, ànd instructs
the train to slow down, speed up, stop, or take any other
action needed.
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