Re: Penna. NG question

I have noted very similar arrangements on a number of shortline and narrow gauge RRs in years past. On some lines, like the B&SR and EBT, gravity switching was possible and used to good effect on a daily basis. Polling or pulling cars onto an adjoining track with a wire rope were also fairly common practices - a recent film on the Westside shows this being done. Some lines (like the Monson and many of the Cuban sugar lines - today) just pulled trains out and pushed them back.
The "flying switch' maneuver was also fairly common in shortline and narrow gauge practice during the 30s and 40s. In one case, the SR&RL, they actually had a complete run-around track in Phillips, yet surviving films from the time show a flying switch maneuver being used. It saved time, there was a slight descending grade, and the maneuver could be done with a degree of safety acceptable for the times.
BTW - if the grade is not extreme, the momentum of heavy freight cars can be used make the "flying switch" maneuver work on an upgrade.
Even today, gravity switching was in use here in Colorado Springs to service a local furniture warehouse until the line in question was abandoned a few years ago.
Best Regards,
Glenn
PS - In the case of the N&SV book, there is a photo taken just before abandonment looking south from the interchange yard. Disused n.g. passenger cars are shown sitting on a siding parallel to the mainline off in the distance. This may have been a passing siding at one time although, by that point my guess is the track was being used solely for storage. Gravity or flying switch maneuvers were probably being used in the yard. I can't answer for the SR&W but again, an upgrade "flying switch" maneuver is possible.