moving the tandems is sometimes easy and most times not. if it's an older trailer with lots of rust and the tandems have not been moved in some time , then good luck.
you have to perfectly straight and on a level surface and sometimes you need 2 people because the handle won't lock into place when you try to move them. I used to bring those long trailers back empty from the rail yard and then would stop by the shop and have them help me move them up. plus you have to make sure both side pins are in the holes before you go. usually the handle won't go in if they are not.
we were never trained to do it. it was just one of those things where you learned it on the job as necessary.