The inclusion of
steep gradients on
railways
Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicles run on a prep ...
avoids the expensive engineering works required to produce more gentle gradients. However the maximum feasible gradient is limited by how much of a load the locomotive(s) can haul upwards. Braking when travelling downhill is also a limiting factor. There have been various solutions to hauling rail mounted vehicles up or down inclines. These include simple rail adhesion,
rack railway
A rack railway (also rack-and-pinion railway, cog railway, or cogwheel railway) is a steep grade railway with a toothed rack rail, usually between the running rails. The trains are fitted with one or more cog wheels or pinions that mesh with t ...
s and
cable inclines (including rail mounted water tanks to carry
barge
Barge nowadays generally refers to a flat-bottomed inland waterway vessel which does not have its own means of mechanical propulsion. The first modern barges were pulled by tugs, but nowadays most are pushed by pusher boats, or other vessels. ...
s). To help with braking on the descent, a non-load-bearing "brake rail" located between the running rails can be used, similar to the rail used in the
Fell system, e.g. by the
Snaefell Mountain Railway on the Isle of Man.
Tramways and light railways often have steeper gradients than heavier railways. This is because all wheels are usually connected to engine power in order to give better acceleration. Grades of 5% are not uncommon on them. Metros and pure commuter railways often also allow steeper gradients, over 4%, for the same reason. High-speed railways commonly allow 2.5% to 4% because the trains must be strong and have many wheels with power to reach very high speeds. For freight trains, gradients should be as gentle as possible, preferably below 1.5%.
Examples
The list below is of some of the steepest gradients on
adhesion railway
An adhesion railway relies on adhesion traction to move the train. Adhesion traction is the friction between the drive wheels and the steel rail. The term "adhesion railway" is used only when it is necessary to distinguish adhesion railways from ...
s, in order of decreasing steepness:
See also
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Grade (slope)
The grade (also called slope, incline, gradient, mainfall, pitch or rise) of a physical feature, landform or constructed line refers to the tangent of the angle of that surface to the horizontal. It is a special case of the slope, where zero i ...
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Hillclimbing (railway)
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Lickey Incline
The Lickey Incline, south of Birmingham, is the steepest sustained main-line railway incline in Great Britain. The climb is a gradient of 1 in 37.7 (2.65% or 26.5‰ or 1.52°) for a continuous distance of two miles (3.2 km). Constructed ...
, steepest British main-line gradient
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Longest trains
The length of a train may be measured in number of wagons (for bulk loads such as coal and iron ore) or in metres for general freight. Train lengths and loads on electrified railways, especially lower voltage 3000 V DC and 1500 V DC, are li ...
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Mountain railway
A mountain railway is a railway that operates in a mountainous region. It may operate through the mountains by following mountain valleys and tunneling beneath mountain passes, or it may climb a mountain to provide transport to and from the ...
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Rack railways
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Ruling gradient
The term ruling grade is usually used as a synonym for "steepest climb" between two points on a railroad. More simply, the steepest grade to be climbed dictates how powerful the motive power (or how light the train) must be in order for the run to ...
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Spiral (railway)
A spiral (sometimes called a spiral loop or just loop) is a technique employed by railways to ascend steep hills.
A railway spiral rises on a steady curve until it has completed a loop, passing over itself as it gains height, allowing the railw ...
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Zig zag (railway)
Further reading
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References
{{reflist
External links
Sample Curve & Gradient Diagram, Page 5
Adhesion railways, gradients
Steepest gradients