I read somewhere that the Northerns built during WW2 for RI, MILW, and D&H was a modified boiler design of the earlier Northerns built for the RI during the 1930s. It might have been in the Trains article on RI Northerns from sometime in 1980.
RI received 10 oil burners in 1944, 10 coal burners in 1946. The coal burners were the last new steam engines built for any railroad operating west of the Mississippi.
Jeff
I remember that article. Miss that type of stuff in Kalmbach’s modern era.
Those wartime units, while generally considered a new standard design for Alco when the D&H units were built, I’m sure still owed a lot to previous 4-8-4’s. Especially Alco-built examples like those Rock units, no doubt.
Those early Rock units are generally considered Alco’s 1st “standard design”, with derivitives being built for the Lackawanna, Lehigh Valley, and Timken (The famous #1111 that ended up with NP after her demo tour ended).
Looking at their statistics, the wartime units appear to sacrifice heating surface for an increased boiler capacity. A 20 psi jump to 270 psi, a significant increase in grate area and the combustion chamber, with a corresponding decrease in flue length.
Lots of changes throughout, some that appear quite substantial when comparing the two. But perhaps close enough where it was presented to the WPB as an evolution of an existing and proven design, even though some historians view it today as a brand new design (I believe Kalmbach’s special issue dedicated to 4-8-4’s a few years back is one such example that takes the view that the wartime units were a new design).
I know WP bought 4-8-4s that were of SP design…and SP bought them when the WP went all diesel in the early 50s.