Union Pacific Big Boy

READ:
4014 slows to 10 mph for a planned meet with a westbound stack train on the 2.2% grade at Alta heading towards Donner Pass.

Enjoy =)

Consist is about 1,550 tons behind the main tender, including the diesel & water cars.

Full Donner Chase:    • Chasing Union Pacific Big Boy No. 401...  

FAQ (Read before commenting):
The water overflow from just in front of the rear cylinder on the fireman's side is the exhaust steam injector overflow port. Discharge from this port is normal when starting and stopping the injector, and when the injector switches between live steam and exhaust steam.

The diesel locomotive, while no longer necessary for PTC compliance, will continue to periodically be used where it is expedient for steam locomotive fuel conservation and assistance on long, sustained grades (power / dynamic braking).