Yeah, but I thought this one was filed under 'gameplay'.  I am not saying they should be doing 25 mph up the hill, but I think it should be possible to climb pretty much any hill.  No reason not too.  If you want to spend 4 hours doing 3 mph up a hill so you can sit and milk run a defenseless city, so be it.  I dont see a huge threat, and hey, if the trains and convoys can do it, we should too.
having to do it in reverse, is well, silly.  even if it is a bug.
Since we can do it, and the sun still rises, I think it should be possible in forward.