switchback

US /ˈswɪtʃ.bæk/
UK /ˈswɪtʃ.bæk/
"switchback" picture
1.

a road, path, or railway with a series of sharp turns, each reversing the general direction of travel, used for climbing or descending a steep gradient

:
The mountain road was full of dangerous switchbacks.
Hikers often encounter switchbacks on steep trails.
1.

to make a road, path, or railway with a series of sharp turns

:
Engineers had to switchback the railway line to navigate the steep terrain.
The trail was designed to switchback up the mountain, making the ascent less strenuous.