Colin
A few years ago I collected a Bridgeport on a low bed car trailer. The supplier loaded it with a fork lift attached to the top eye. At home, I put a 2 ton engine crane around it to lift from the top eye and tried to ease the crane down the, now tilted and jacked, trailer and onto concrete. The problem was the solid iron engine crane wheels on solid axles – it all bound up and stuck to any surface on the trailer. No risk of a runaway! we had to pry bar it down with retaining safety check straps being eased in stages.
Then when it was on the concrete those wheels just dug in and would not roll. It was pry barred into the workshop door, then lowered onto steel bars to roll it into position – much easier to rotate, etc. You need heavy, long pry bars and at least three chaps. At least while on the engine crane it could not topple, once off the crane we took it very cautiously.
Best of luck.