To my knowledge, the steam would go directly to the coaches from the loco boiler.
Yes, but through a pressure reducing regulator mounted on the locomotive. In the switch over from steam power to diesel there would be a boiler on the diesel to supply steam for heating. As well electric locomotives such as the GG-1 had steam heating boilers to do the same. This made it simple to keep the equipment interchangable in between locomotive types.
Each car had a heat exchangers that were very similar to a household baseboard heating radiator and normally ran the length of the car along the floor on the outside coach wall. The steam trainline was connected at each end by a very sturdy built connection that was made of pipe with knuckle type flex devices to allow for movement. At the rear of the train you would see a steam telltale trailing from the trainline, this was to drain the condensate from the line as it was a total loss system. On the big name trains,many times you could board ahead of time to get settled in and the cars would be heated by a connection to the terminal powerhouse to prvicde heat before the engine would back down on her train. This was especilly true with the railroads that had overnight sleeping car service with late day departure times.
Later the advent of HEP and electric car heating eliminated the steam heating systems in most passenger equipment.This is one of the reason you see mainline steam excursion with a diesel in the consist to supply HEP in the absence of a dedicated power car.There are still a few tourist railroads that have rolling stock equipped with steam heating system,with New Hope and Ivyland coming to mind.
It is possible that an electric generator was mounted at the rear of the tender using the steam line going to the coaches for a steam source.
The tender mounted auxilary turobo-generator supplied electric to the batteries for lighting in the coaches. Each car had a generator slung mounted underneath with a drive belt to one of the truck axles which then would supply charging voltage to the battery banks. But due to the stop and go nature of the CNJ's commuter runs,the batteries wouldn't always get fully charged in between stations.
Fix: the auxilary generator . The generator would run off a steam line at boiler pressure much the same as the generator for the locomotive electrical system. There was a train line that would be connected between the coaches supplying charging voltage. Some other railroads used a larger or dual turbo generators for the locomotive electrical system and supplied train line voltage from them. The old electrical systems were 32 volts or 64 volts. HEP power supplied now is 480vac 3 phase for heating and A/c with lighting systems on 120vac panels in each car.
Help any??