The N&W routed their blow down/sludge remover under the engine cab just as shown in the video. I suppose the PRR did the same on the T1
Every locomotive that I have seen, in either real life, or in photos, that is equipped with the Wilson system, has the "sludge" discharge chute located under the Engineer's cab, down low, so as to discharge the "sludge" onto the right-of-way, but also located so that the Engineer can see the condition of the "sludge" be discharged. The actual circular separator "turbine" device is located on top of the boiler/firebox area, and exhausts the steam vertically to atmosphere. Thus, when either the Engineer or the Fireman is using the "sludge remover", there is a big vertical steam discharge from just forward of the cab (turret area), and hot steaming "sludge" water discharged under the right side of the cab, on to the right-of-way.