Thanks everyone for the advice. I did try some magnets but they were not good strong enough and the train would become uncoupled on the front engine. The train is heavy and long enough that I need to power it from both ends for it to move well and the problem I kept getting, among other issues with derailing, was the front engine detaching. I have used some technic pieces to replace the couplers and that seems to be working now.
Hopefully within the next month or so I will share off the creation that is almost a year in the making.