To quote GRJ...You may consider a TVS across the pickups of a locomotive to be overkill, and you have every right to hold that opinion. My opinion is the TVS is a valuable transient protection device, and for the 50 cents I spend on them in quantity, I plan on continuing to use and recommend them.
My question is could i install the TVS across the red and black wires (the ones with wire nuts) above the boards or at the trucks?..across the wire nuts all kinds of room..at the trucks not much room.