To the point, I creamed my pants seeing a railroad utility truck spin out trying to get up a snow filled lane. Made it partway up, came to a dual tire spinning halt, backed down half a truck length, try again, didn't even make it as far as before, before spinning out on snow, another backdown. Must of dropped its right dual tires in a small hole at the edge because it just sat and spun. That instance was when I jizzed myself. The truck couldn't even back any further, just spun out in reverse. Finally caught some traction and got up the grade.
I worked for the railroad at the time. Few years later as a crewman on a long loaded stone train, I shot a load a time or two as the engines stalled on a grade with its train. Engineer I was with got it out of its stall and up grade.
Know that train wheels have rail surface contact equal to a small coin with all that weight. Oil, grease, rain, leaves in autumn, snow in winter can cause trains to lose grip on rails. Unable to start from a stop or slide past a stopping point. Trucks get stuck, trains stall.