ループ線せん

noun

spiral railway line; loop line

A curving railway track that spirals to gain elevation on steep terrain, common in mountainous areas.

• 山さん間かん部ぶでは、急きゅう勾こう配ばいを登のぼるためにループ線せんがよく使つかわれる。

  In mountainous areas, spiral loops are often used to climb steep gradients.