Thanks @AGHRMatt ... I have some newer MTH cars that have the pads and Iam compiling a list of items I need to convert them. Do you buy the scale trucks or just change out the wheelsets?
It depends. On my Centerbeam cars, I changed out the trucks from the MTH 3-rail to Weaver plastic trucks with Intermountain 33" steel wheels. On a pair of MTH gondolas, I switched the trucks out for MTH 2-rail trucks which gave the cars the correct ride height, then installed Kadee 740 couplers. On another car, I used the MTH hi-rail trucks with Intermountain wheels. It really depended on what I had in the parts bin at the time and which would be easier for the particular situation. Replacement trucks can get expensive, but the new MTH trucks are a pain to disassemble/reassemble. I'm looking at the newer Atlas 2-rail trucks which have the adapter plug for use with MTH cars. I have a project in the pipe -- converting two strings of MTH Gunderson cars to 2-rail. For now, each string is a massive "transition car" with a Kadee on one end of the string and the hi-rail coupler on the other with the hi-rail wheels still in place since I run them at the club (like I said, I'm operating in both worlds right now).