@rrman posted:I always assumed (wrongly I guess) that particular diesels (Amtrak, CSX, BNSF etc) were required for PTC information and/or responding to cab signals for the particular road, and to give a shove if necessary, otherwise they were just along for the deadhead ride.
Actually the Cab Signal equipment, as well as any PTC equipment, must installed be on the lead/controlling locomotive. That is why NKP 765 is herself equipped with the former PRR, now NS, Cab Signal & and Train Control system, and really doesn't require a diesel behind (except for long moves in order to stretch coal usage, as Rich has already explained).
On steam excursions operating under the Amtrak insurance umbrella, such as more recent SP 4449 trips, the Amtrak diesel provides HEP (480 volt three phase AC) for the passenger cars.
Currently, the UP is experimenting with a "remote" PTC system on the trailing MU'ed diesel unit, with some sort of controls to the air brake system on 4014 (simplified explanation) . Attempting to have the PTC computer screens mounted and powered in the cab of 4014, or another steam locomotive, is quite a challenge.
