UP 2-8-8-0's

[Fr.Al]

I was pleased to get the latest special issue of CT and read about a fireman's experience on these engines. When one thinks of articulated locomotives and the UP,  Big Boy and Challenger come to mind. It seems that the 2-8-8-0's were built as Mallets and later converted to simple articulateds.

[Overmod]

Don't forget the ones that got tender boosters from 4-12-2s!

[Fr.Al]

[quote user="Overmod"]

Don't forget the ones that got tender boosters from 4-12-2s!

 I wasn't aware of that. Does that mean those 4-12-2's were then scrapped or did they remain without the boosters? Incidentally, it seems that those 4-12-2's were among the most successful three-cylinder steam locomotives. They did last until the 50's

[Overmod]

The 4-12-2s were the subject of a quiz question a few months ago.

I believe if you google Oregon Short Line you can read most of the details, but you have to put a few posts together.  The Alco three-cylinder innovations of the first part of the '20s, culminating in the Nines, coincided with the period of experimentation with boosters and auxiliary locomotives after 1921.  Since a booster on a Nine would only involve one axle, the idea of an auxiliary locomotive on the tender (to boost starting TE) was a less unsensible way to go.  

Of course those wobbled like all the other auxiliary locomotives, and when it became clear that the first best use of those Nines was in faster freight service, the tender boosters used came to be applied to 2-8-8-0s (which of course had no trailing axles to fit with boosters...)