I have this urge to run a pair of F3's or two FM's together on three rail (054 & 072) gauge track. I own a Lionel trainmaster FM. If this forum explains how its done; I'd run two engines in tandem. What do I look for in the used diesel market that assures me that the two engines are compatable? What must I do to link them together? I do not use comand control, just 140W MRC transformers. Is there another brand, Atlas Weaver, K Line or MTH that offers a solution? Thanks.