noun
spiral loop; spiral railway line
A railway engineering term for a curving track that spirals to gain elevation on steep terrain. Also referred to as ループ線.
See also: ループ線
この山間部には、急勾配を登るためのループラインが敷設されている。
A spiral loop has been laid in this mountainous area to climb the steep gradient.
Railway enthusiasts know the best spots to photograph the spiral loop.