I have to differ with those that are saying there was no Y in the vicinity of West Barstow Tower. IIRC there was a Y however it was very tight radius and had a very short stem and therefore could not be used to turn entire trains. And yes, the Mojave Y was a disaster even in the 60-70 era; IIRC it was way over on the north side of the SP yard anyway. As far as the SWG-GWS (Santa Fe-Western Pacific-Great Northern) and reverse. Prior to NEW Barstow, it would come in on the main lines and turn right there by the old power coming off and going to Diesel Service thru East Tower while the new power got on the West end. Can't confirm or deny the cab on each end but that seems to be correct as this move was HOT HOT HOT. It was direct competition to the SP that had a much shorter route.
Another interesting main line movement with a cab on both ends was the San Berdo San Diego flip when the Olive district was out of service for several months due to flood damage. Andy