Although it appears possible to get off the railway to go into the ravine, do not do this. The player will die. Unless you use a rope to tie off to the rock just to the right of the tree which then leads to the Ravine Basin.
To traverse the new version of Ravine, you have to abandon the rails and go to the right. As soon as you see a way to the left, follow it. You will also usually find a frozen corpse and some Rose Hips there. Cross the fallen tree onto a derailed cargo wagon, then go on following the rails until you get to the bridge.
There is a cave in this area. It is located where the rock wall makes a very sharp bend (almost a 90 degree bend) on the side furthest from the tracks. This makes a great place to rest if climbing up from the Ravine Basin.