B&M R1 Mountain

Engineer Spike--
O.k., that makes sense: B&M didn't have enough diesels to cover everything when they sold most of the R1 to B&O, so kept the newest ones to use. (And maybe, by the time they were ready to release their last R1, the B&O was no longer interested in second-hand steam. The B&O was a fairly "early adopter" of diesels -- they had early switchers, the first EMD E units, and some FT -- and probably kept using steam as long as they did (1958, I think) only because they didn't have the money to by replacement diesels. So there may have been only a short period when they thought it was worth while to buy cheap steam to tide them over until they could afford more diesels.)

One point that I filed to mention was that, which what ever inadequacies they had, the R1 design was copied. Lehigh and Hudson River bought some too. The L&HR fleet came during the war. At the time proven designs were all that was allowed. Furthermore, if B&M wasn't satisfied, they wouldn't have gone trough four batches, which were delivered on the odd numbered years between 1935, and 1941.

In the end, they were not able to keep up the pace of wartime traffic.Especially on the mountainous Fitchburg Division. The other handicap was the need for steam power to bank their fires, then get towed through the tunnel, then build up the fire on the opposite end. This lead to the government allocating the purchase of a fairly large FT fleet.

The three L&HR 'war baby' 10-class were R-1d copies (with several very small detail differences) from 1944. Baldwin builder's photos...

Thanks for the detailed answers. They have lead me to a few thoughts in summarization. Maybe Lima was a bit overboard in the calculations of what sized firebox was needed to have the steam production rates needed to have a large locomotive sustain high demand steam load? Maybe in the boom times of the 1920s the waste on excess sized fireboxes wasn't a problem, but later they had to focus more on the economy of efficiency. Perhaps the understanding of thermodynamics became more refined too. The addition of syphons in the fireboxes might have made a more compact design be able to more efficiently produce the same quantity of steam.

One of the quoted articles also mentioned the P4. These Pacifics were built late, at a time when many other roads, including sister Maine Central was buying Hudsons. Maybe the thought process was the same in arriving at a single axle trailing truck. The P4 class was also built by Lima. Maybe they had changed their mind about what super power really was. Who knows it that was a factor or not. The first P4 order predated the R1 by about a year. One has to wonder how much of the final products was conceived by Lima and Baldwin, or B&M's own engineering staff.