Grade (slope) - Railways

Railways

Gradients limit the load that a locomotive can haul, including the weight of the locomotive itself. On a 1% gradient (1 in 100) a locomotive can pull half (or less) of the load that it can pull on level track. (A heavily loaded train rolling at 20 km/hr on heavy rail may require ten times the pull on a 1% upgrade that it does on the level at that speed.) Early railways in the United Kingdom were laid out with very gentle gradients, such as 0.05% (1 in 2000), because the early locomotives (and their brakes) were so feeble. Steep gradients were concentrated in short sections of lines where it was convenient to employ assistant engines or cable haulage, such as from Euston to Camden Town, about 1.2 km. Extremely steep gradients need the help of cables, or some kind of rack railway.

Gradients can be expressed as an angle, as feet per mile, feet per chain, 1 in n, x% or y per mille. Since surveyors like round figures, the method of expression can affect the gradients selected.

The steepest railway lines that do not utilize a rack system include:

• 13.5% (1 in 7.40) - Lisbon tram, Portugal
• 11.6% (1 in 8.62) - Pöstlingbergbahn, Linz, Austria
• 11.0% (1 in 9.09) Cass Scenic Railway USA (former logging line)
• 9.0% (1 in 11.11) - Ligne de Saint Gervais - Vallorcine, France
• 7.1% (1 in 14.08) - Erzberg Railway, Austria
• 7.0% (1 in 14.28) - Bernina Railway, Switzerland
• 6.0% (1 in 16.7) - Arica, Chile to La Paz, Bolivia
• 6.0% (1 in 16.6) - Docklands Light Railway, London, UK
• 5.6% (1 in 18) - Flåm, Norway
• 5.1% (1 in 19.6) - Saluda Grade, North Carolina, United States
• 5.0% (1 in 20) - Khyber Pass Railway, Pakistan
• 4.0% (1 in 25) - Cologne-Frankfurt high-speed rail line
• 4.0% (1 in 25) - Bolan Pass Railway, Pakistan
• 4.0% (1 in 25) (211.2 feet per mile) - Tarana - Oberon branch, New South Wales, Australia.
• 4.0% (1 in 25) - Matheran Light Railway, India
• 3.7% (1 in 27) - Ecclesbourne Valley Railway, Heritage Line, Wirksworth, Derbyshire, UK
• 1.66% (1 in 60) Rudgwick platform with non-continuous brakes - too steep.
• 1.51% (1 in 66) (one foot per chain) New South Wales Railways, part of South line.
• 0.77% (1 in 130) Rudgwick platform with non-continuous brakes - not too steep.