I can't really say for sure what went on in the P&WV days, but after the N&W take over the N&W power would normally be left on what ever train it came into town on. This was especially true for the Alpha Jet trains. The N&W power would almost always be left on to Cumberland and sometimes Hagerstown. This was also the same for the unit grain trains that the N&W began to run in the early 70's, this power would stay on the whole way to Hagerstown 99% of the time. Usually the only reason that these trains would stop at Bowest was to change crews and then they would be on the move again. On the other hand WM power would also continue west on most through trains. For the most part the WM power would run west to Rook where it would be swapped out, this did occur during the P&WV years and continued into the N&W era. However later on in the N&W era the WM power began to run further west before being taken off its train. Although often by this point in time the consists on the Alpha Jets would often be a hodge podge of WM and N&W power. Also during the 70's N&W cabooses were required to stay on all Alpha Jet trains due to a union agreement. I am not real sure what went on with trains that had a lot of work in Bowest yard though. From what I have gathered with these trains the power would be swapped out, but this was due to the fact that the entire train would have to be backed into the yard in most cases. Also between the the WM/P&WV/P&LE connection and bowest there was a small yard, Greenwood, that served as the Pennsy interchange yard.