You always tried to open the coupler on the remaining train or cars left in a yard. This way the coupler is open when the cars or train has to be again coupled to, No need to stop and open a coupler. Lots of guys working a yard uncoupling a engine would use the engine, s operating lever instead of the car(s). Not a big deal but just saves a little time the next time the cars have to be moved.
most rail cars only have one hand brake.... They can be facing any direction in a train. It 's just how they end up over their journeys.