Spiral (railway)


A spiral 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 railway to gain vertical elevation in a relatively short horizontal distance. It is an alternative to a zig-zag, and avoids the need for the trains to stop and reverse direction while ascending. If the train is longer than the length of each loop it may be possible to view it looping above itself.
The term "loop" is also often used for a railway that curves sharply and goes back on itself: if the railway crosses itself, then it forms a spiral or helix; otherwise, it forms the much more common horseshoe curve or bend.

List of spirals

Argentina

Australia

Bulgaria

Canada

China

Costa Rica

Replica of the Brusio Spiral Viaduct at on the Tren Turistico Arenal, 10 km east of Nuevo Arenal, Guanacaste.

Croatia

Eritrea

  • Spiral between Asmara and Arbaroba at on Eritrean Railways. This spiral pushes the definition of a spiral as the line crosses itself but then immediately crosses back, and it does this in a tunnel.

France

Germany

India

The Darjeeling Himalayan Railway originally had five or six spirals but only five in operation at any one time. The line also has six reverses or zig-zags.

Iran

Ireland

Italy

Japan

Kenya

There are three spirals on the gauge railway line from Kenya to Uganda. This railway has been superseded by the Mombasa–Nairobi Standard Gauge Railway, which has removed the need for spirals by constructing tunnels and bridges.
  • Spiral South of Mazeras at near Mombasa.
  • Spiral near Makutano station at :.
  • Spiral near Equator station at.

Madagascar

Mexico

Myanmar

New Zealand

Norway

Peru

Russia

Serbia

Slovakia

South Africa

South Korea

  • Spiral at Hambaek 1st Tunnel at between Hambaek station and Jodong station on the Hambaek Line;– one loop, single track.
  • Spiral at Solan Tunnel at between East Baeksan station and Dogye station on the Yeongdong Line. There is one loop on a single track railway but double track is installed in the middle of the tunnel to enable trains from opposing directions to pass each other.
  • There used to be a spiral at Daegang Tunnel at between Danseong station and Jungnyeong station on the Jungang Line;– one loop, single track. A new double track tunnel has opened which by-passes the line with the spiral, which has since closed.
  • There used to be a spiral at Ddwari Tunnel at between Geumgyo station and Chiak station on Jungang Line. A new double track tunnel has opened which by-passes the line with the spiral, which has since closed.

Spain

Sri Lanka

Switzerland

Taiwan

  • Triple spiral at Dulishan at on the Alishan Forest Railway. Track length is 5 kilometers, while the endpoints of the spiral are only 570 meters apart horizontally and 233 meters vertically.

Uganda

United Kingdom

United States