Steam train

[Ulzgoroth]

Originally Posted by Varyon

It's all going to be very context-dependent. Perhaps the tracks go through multiple independent polities (likely for a post-apocalyptic setting, as in the OP) and you're basically stealing the train that was bound for one polity (that you're on - or at least willing to be on - bad terms with) and rerouting to another (that you're on better terms with, and that isn't on good terms with the polity you stole from, such that you can readily sell your cargo). Perhaps it works out better for you if you can steal the train at an ideal ambush-point, then take it to a point closer to your bandit camp (or whatever) and dump the cargo (which can be quickly transported by wagons going back and forth), then go elsewhere to abandon the train (preventing the relevant authorities from working out where your camp actually is). Perhaps some trains in your setting engage in speculative trading, and the heist is actually to steal the train and act like you're the rightful owners to sell off the cargo at the originally-intended destination.

Or maybe you're not all that great at this "bandit" business and you have a plan that reads:
1) Setup temporary blockage
2) Steal train
3) ????
4) Profit!

Railroad border crossings are always going to be secured - you won't be passing through without inspection unless the two sides of the border have exceptional relations.