I forgot, the SP American switch lock body was put on the GE locos SP ordered at the end with a sliding bolt style. GE then continued to sell locomotives using the same key to other RRs. The BNSF GEs all came with that lock later. The AAR issued a standard several years ago specifying the SP key. A friend of mine who is a BNSF engineer had great fun locking the doors at an awkward time for the carrier with the key I provided him---this of course before BNSF issued the keys.