Since this Alco has a front coupler, you might experiment with running it backwards. That would put the motor in the rear for you. Of course, be sure the cars roll freely, too. Who knows? It might work. If so, then a shell-swap like DanssuperO suggests would be a simple and adequate solution. Though, I would use an MPC Alco rather than a postwar 200 series: better (more rigid) drive train, die cast sideframes on the rear truck for extra weight, already has traction tires. No magnetraction, but IMHO, if you already have tires, the magnetraction is superfluous.