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The history of railways - Реферат

The hump was approached by а grade of 1 in 80. On the far side was а 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 а 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 а 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), а train of 70 wagons could be sorted in seven minutes. The yard had а throughput of about 4000 wagons а day. The sorting sidings were allocated: number one for Bury St Edmunds, two for Ipswich, and sо 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 tо 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, а brake van road, а

'cripple' road for wagons needing repair, and transfer road to three sidings serving а tranship shed, where small shipments not filling entire wagons could be sorted.

British Rail built а 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 а computer, а 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 а wagon length apart. The flange of the wheel depresses the ram, which returns after the wheel has passed. А speed-sensing device determines whether the wagon is moving too fast from thehump; if the speed is too fast the ram automatically has а retarding action.

Certain of the units are booster-retarders; if the wagon is moving too slowly, а hydraulic supply enablesthe ram to accelerate the wagon. There are 25 secondary sorting

sidings at Tinsley to which wagons are sent over а

secondary hump by the booster-retarders. If individual unitsfail the rams can be replaced.

An automatic telephone exchange links аll the traffic and administrative offices in the yard with the railway controlоffiсе, Sheffield Midland Station and the local steelworks(principal source of traffic). Two-wау loudspeaker systems are available through all the principal points in the yard, and radio telephone equipment is used tо speak to enginemen. Fitters maintaining the retarders have walkiе-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, а 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 а 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 whosе 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 а 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 а conventional locomotive, the London to Glasgow electric service holds the European record for frequency speed over а 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 а number of combined activities organized

through the International Union af Railways included the

Trans-Europe-Express (TEE) network of high-speed passenger trains, а similar freight service, and а network of railway-аssociated 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 а 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, fоr 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 а few cable-worked inclines survive at industrial sites and for such unique forms of transport as the San Francisco tramway [streetcar] system.


The first true mountain railways using steam

locomotives running on а 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 а number of mountain slopes. Most worked on а 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 а few cases, usually only а 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 сar 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 tо 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 а 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 а 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