Video: World's Largest Steam Locomotive in Action!
 

Union Pacific's 4-8-8-4 "Big Boy" Locomotive on an excursion through the State of Minnesota, USA.

Chase video:

https://www.youtube.com/watch?v=weUzhScDNps&t=115s

G'day Doctor,
I have just copped some digital images featuring that leviathan soot belcher from a buddy who chased it.
I will eagerly await copping his video footage of it.
Gotta say that it is indeed most impressive.
When I am next at the local library (freebie www), I will attempt to snag your You Tuber footage.
Steve.

Great stuff. I see that there's a diesel loco in the consist. Is that there to provide head end power for the train, or just as an insurance policy?

BW

I thought all these were oil burners, so was surprised at the black smoke. Looking it up only one was converted to oil burning, 4005, in 1946 and converted back to coal in 1948. This one was converted to oil during restoration.

The diseasesel was there to use it's dynamic braking to provide additional load as part of the running in process.
As far as black smoke is concerned that is produced when too much oil or not enough air is going through the fire. This usually happens when there is a need to increase the firing rate by adding another burner. Black smoke is unburnt carbon and producing it is inefficient because it is not extracting the greatest heat from the fuel. Remember that the fireman on this trip would be learning how to control the fire on that locomotive which has a bigger firebox than the only other operating Union Pacific locomotive. 4014 was converted to oil as part of its restoration.

Grosvenor you are a mine of information.

Ah yes, black soot from an oil burner.
Our NSWR 59 class 2-8-2 Baldwins were delivered as oil burners.
The NSWR converted them to coal eventually.
We have heaps of black diamonds but had to import oil in them days.
Many residents living along side the Main North would whinge about greasy washing after an oily 59 chuffed past.
One technique employed to clean the gunge out was for the fireman to open the fire box inspection flap and hurl in a handful of sand.
This cleaned the flues.
But, the soot belcher spat out a big plume of greasy exhaust as the sand did it's effect.
Steve.

Steamers are notoriously inefficient even in the 21st Century. The SD70 is there to provide power when the Big Boy breaks down. Fortunately, it has not broken down at any time during it's tour of the Upper Mid-West.

However, it does require maintenance stops about every 50 miles.

To my knowledge there is only ONE coal burning locomotive left in the world that's operational. It's the Steamer #261.

https://261.com/

I think you meant to say in the United States, DoctorZ! :D