Large Scale Central

Replacing Backmann Trolley with some other power block

I am seeing a lot of posts about replacing the Bachmann open air Trolley with other brand power blocks however, all the images for each of these posts are not available.

I see suggestsion of using:
USA F-3 motor block
Aristo 29351 diesel brick
Aristocraft FA motor block

Which is recommended…and…can anyone point me to any step by steps of how to do this here on the forum (with images preferably)?