One of the last Conrail painted units passes the closed Homan Ave tower with a bottle train. Before the overpass was finished in 1995 this was a very busy diamond with the IHB, NYC, Erie, the C&O, Monon, and the NKP.
It was also one of the last crossings that didnt have electric flashers and were controlled by a watchmen in a smaller tower behind me until about 1987.
hmm maybe each bottle car works like a DPU but only for making air for the car behind it? or maybe they just use steel lines like those used for natural gas supply lines