UP 844 & SP 4449 Arrive at Edmonds, WA. 5/18/07

[stevelerro]

Finally a trip not ruined by diesel helpers, and instead a helicopter has to pace the train and ruin it for everyone trying to video tape...

[Jemalacane]

What powers the pump for the air brake system on a steam locomotive?

Also, where is the air tank kept for the air brake system?

[DanielVolker]

@Jemalacane

The air pumps are powered by steam. On a cross compound compressor (the 4449 and 844 both have two) a single pump has two pistons: one where hish pressure steam pumps low pressure air, the air and steam then move to a larger cylinder where the now low pressure steam again compresses the air.

[HorsegirlJenny]

Awesome video! Great angle on them approaching. What a beautiful pair. :D I love where 4449 starts her whistle then 844 chimes in. YEAH!