Pack of four train magnets for our block detector systems, .5 or .6 inch  diameter rare earth really strong magnets. Mount on engineer's side (front of train) and fireman's side (rear of train) to trip/reset block detectors. Simple to mount with epoxy or nut/bolt combination. The .6 inch version has a hole for a mounting screw.  Will clean up any stray ferrous metal track FOD... (You'll be amazed at all those missing screws you find).

The solid (.5 inch) version is slightly more powerful but must be mounted with epoxy (or two magnets).  The .6 inch version has a mounting hole that allows you to use a 4-40 or 2-56 nut/bolt to mount.