Vertical easement

A vertical easement is the rounded transition between two track sections of different slope — at the foot of a ramp (a sag) and at its crest. A sharp grade break makes long vehicles ground out or lift off, because their rigid wheelbase cannot follow the kink; couplers and buffers jam. The change of gradient is therefore eased gently over several centimetres. The Trackplanner’s operations check warns about grade breaks without an easement.