Cable railway
From Wikipedia, the free encyclopedia
A cable railway is a railway that uses a cable or rope to haul trains.
There are three distinct forms of cable railway:
- Cable car systems for mass transit of passengers
- Funicular railways, where the cars are permanently attached to the cable
- Steeply-graded cable railways, used for freight, as described in this article.
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The gradient of these lines is typically so steep that a conventional rail adhesion train could not climb the track. Most commonly the cable is operated by a stationary engine, although other methods such a gravity or water balance are also used.
Many cable railways connect to conventional adhesion lines at their top and bottom, allowing trains to be lifted from a lower line to a higher one. A specific type of cable railway is the funicular, which is a self-contained railway, unconnected to another line. This requires the loading and unloading of passengers and goods at both ends.
In the United Kingdom cable railways are sometimes known as "inclined planes" or simply "inclines".
Level tracks are arranged above and below the gradient to allow wagons to be moved onto the incline either singularly or in short rakes of two or more.
On the incline itself the tracks may be interlaced to reduce the width of land needed. This requires use of gauntlet track: either a single track of two rails, or a three-rail track where trains share a common rail; at the centre of the incline there will be a passing track to allow the ascending and descending trains to pass each other.
Railway workers attach the cable to the upper wagon, and detach it when it arrives at the other end of the incline. Generally, special-purpose safety couplings are used rather than the ordinary wagon couplings. The cables may be guided between the rails on the incline by a series of rollers so that they do not fall across the rail where they would be damaged by the wheels on the wagons.
A few inclines hauled locomotives up using the cable, but these were comparatively rare as it was normally cheaper to provide a separate fleet of locomotives on either side of the incline, or else to work the level sections with horses.
On early railways, cable-worked inclines were also used on some passenger lines, for example at Cowlairs in Glasgow.
A stationary engine drives the winding drum that hauls the wagons to the top of the inclined plane and may provide braking for descending loads. Only a single track and cable is required for this type. The stationary engine may be a steam or internal combustion engine, or may be a water wheel.
In a gravity balance system two parallel tracks are employed with ascending trains on one and descending trains on the adjacent track. A single cable is attached to both trains, wound round a winding drum at the top of the incline to provide braking. The weight of the loaded descending cars is used to lift the ascending empties.
This form of cable railway can only be used to move loads downhill and requires a wider space than a stationary engine driven incline, but has the advantage of not requiring external power.
This is a variant of the gravity balance incline that can be used to move loads uphill. The weight of the unloaded descending train is increased using water until it is greater than the train travelling uphill. At this point gravity allows the uphill train to ascend. The water is either carried in an additional water wagon attached to the descending train, or is carried in a platform on which the train descends.
This form of incline has the advantages of a gravity balance system with the added ability to haul loads uphill. It is only practical where a large supply of water is available at the top of the incline.
An uncommon form of cable railway uses locomotives to power the cable. The cable is attached to a locomotive, usually at the upper end of the incline. The locomotive is driven away from the head of the incline, hauling wagons up the inclined plane. The locomotive itself does not travel on the steeply graded section.
This is most commonly used for a temporary incline where setting up the infrastructure of a winding drum and stationary engine is not appropriate.
- Cromford and High Peak Railway opened in 1831 with grades up to 1 in 8.
- Liverpool and Manchester Railway
- Opened with cable haulage down 1 in 48 grade to dockside.
- Designed with for cable haulage up and down 1 in 100 grades at Rainhill just in case locomotive haulage was impracticable. Rainhill Trials showed that locomotive could handle 1 in 100 gradients.
- The São Paulo Railway in Brazil was originally a cable railway, later a rack railway.
- The Welsh slate industry made heavy use of gravity balance and water balance inclines to move slates from quarries down to transhipment points. Examples of substantial inclines were found in the quarries feeding the Ffestiniog Railway, the Talyllyn Railway and the Corris Railway amongst others.
- Pittsburgh, Pennsylvania has two incline passenger cars (or funiculars) that travel between the top of the Mt. Washington hillside to Station Square at the base of the mountain along the Monongahela River.
- The Lynton and Lynmouth Cliff Railway is an operational example of a water-balanced incline.
- Chattanooga, Tennessee has an incline railway that travels from the base to the top of Lookout Mountain.