The title of this post is from an Army Subcourse TR 0690 - Loading, Blocking, and Bracing on Rail Cars. If anyone wants to prototypically do that .. blocking and bracing then this is a good guide since it is an instruction course for soldiers to do just that - for real. On page 29 it talks about 'Spanners' .. used to bridge the gap between flat cars. They make it sound easy. I was on a Rail-Load Team once .. we loaded an entire Brigade .. tracked and wheeled vehicles. There was a string of at least 50 flat cars .. and we had to carry the spanners and set up for each two cars. HEAVY aluminum plates .. THEN .. try driving a tank off of the loading dock at 90° to the rail car and then when half-way across you pivot the tank so you are facing long-ways on the flat-car. This is all done using a guide .. since from the driver's compartment you can't see anything but sky and distant ground. THEN .. you are ground guided down the flat-car .. and across those spanners .. to the next flat-car and then the next .. perhaps twenty cars at first. That is when you HOPE the guy directing you knows what the heck he is doing!