Herb, the branch pipe runs from the injector to the check valve near the front of the boiler. The draw pipe runs from the tender tank to the injector. I was warned by someone that all piping ought to be replaced, but my bad, I forgot. They had lots of scale, and that caused stuck check valves the first day. they were also cracked and thin. In the best of all worlds a restored locomotive should get all new piping, but with such a dilapidated unit we had to draw the line somewhere.
The steam header pipes or "wishbones" run from the throttle pipe to the cylinder saddle in the smokebox. These sprung a leak during a hydo, and we addressed these thouroughly. All the steam was from the engine "dead centering" or on the turntable. This was a result from getting stuck on a a dead beat from the engine being out of time.