I work with a lady whose son is a conductor for NS. He found out I love trains and sent me a "Handle, Locomotive Reverser (Black) (Versylon)." http://www.milleringenuity.com/Products/Parts/MarketCategory/Controller Handle Part What is it and what was it used for? - Brandon
You insert it into the proper slot on the locomotive's control stand, and is used to place the engine in forward/neutral/reverse. The particular type he sent you (I suspect) will work for any EMD product with the AAR-type control system.