The postwar 497 has it's control track rails built right into it. You will not need to use an operating uncoupling track just install a section or two of normal O27 strait track. The tracks snap into slots in the frame of the platform similarly as the milk and cattle corrals do.O27 track snaps on the bottom, lowest notch. Gargraves mates with O27 nicely. Just pick up a set of O27-Gargraves mating pins.
The 497 was designed to work with shoe activated Postwar dump cars like the 3459 or 3469. It will not work with newer cars that do not activate by shoes. You will also need to use the O27 blade.
MPC and Lionel reissues of the 497 were redesigned to use an ordinary remote control track that are compatible with most other dump car styles.