The transformers RCA made for that rig are robust, judging by the mod. transformer and reactor. It's kind of unconventional to bolt them to the front of the cabinet instead of the bottom but that let them use a cabinet that isn't very deep. I am guessing the bolt holes are tapped so no nuts are needed on the other side. The iron on the right (the mod. transformer, reactor and what looks like a filter choke) can probably be removed by one man unscrewing the final upper bolt with one hand and easing the iron down to the one just below it or the bottom. The plate supply transformer is tougher--looks to weigh around 100 lbs or so. May never need to be removed but if so, there are three ways: two guys one holding the other unscrewing, one guy and a chain or cable to hold the iron, or tipping the whole box forward onto a blanket so front is now the bottom. Observe that the front panel knobs are recessed. There was a reason for that apart from looks. I'll bet when that rig was assembled at RCA, the box laid on its front on a mat on top of a roller conveyor and they set the iron in and bolted it down. The rig was probably assembled with the cabinet being one big tray.