it’s a GS-4 class, 4-8-4 Northern type steam locomotive, constructed by the Lima Locomotive Works on the 1940s for the Southern Pacific railroad, for use on it’s signature passenger train known as “The Daylight”
@@kingofthepod5169 4449 was built with three Turbos because of the electricity required on her. One turbo is dedicated to running most of the loco's lights and electronics, another one is a 12V model which is dedicated directly to just running the Mars light, and the third was originally used when she was in revenue service to power the SP Daylight's Electro-pneumatic braking system, and now is used to power the Christmas lights for the ORHF's annual Holiday Express excursions
So the air pump makes that "WHOOH-TOOH" sound on steam locomotives? I always hear it but I don't know is the sound coming from air pumps or water injectors?
The air pump on most engines are muffled and end up sounding like that with the clicking sound. On smaller engines, the air pump exhaust is out the smokestack and creates a chuffing sound, even when the engine is sitting still. Water injectors are usually just a vacuum sound, without any clicking.
I’m not 100% on this but from what I understand these are cross compound pumps. Essentially the steam starts on one half of the compressor (if you split it down the middle from the top to the bottom). On that half of the compressor, the steam is used in a high pressure steam cylinder, which pushes on a low pressure air cylinder above/below it. Then the steam is exhausted to a much larger low pressure steam cylinder on the other half of the compressor. The air that was compressed in the low pressure air cylinder exhausts to the high pressure air cylinder, which is pushed on by the low pressure steam cylinder. Hence, cross compound.
