Selective Momentum
The faster a train can go, the more momentum it has, and the less of a problem a steep gradient is.
Train speeds may however be restricted by light track. It tends to be the case that the lightness of the track will be uniform throughout an operating district.
If the track is upgraded approaching a steep gradient, train speeds and momentum may be raised just where it is needed most. This needs heavier rails, more sleepers, and more fixtures.
Read more about this topic: Ruling Gradient
Famous quotes containing the word selective:
“The selective memory isn’t selective enough.”
—Blake Morrison (b. 1950)