by Pneudyne
Returning to the original question, and looking more closely at a selection the pertinent Baldwin-built locomotives:
AT&SF:
1938 4-8-4 Baldwin disc
1938 2-10-4 Baldwin disc
1941 4-8-4 Baldwin disc.
1943 4-8-4 Boxpok
1944 2-10-4 Boxpok
B&M:
1935 4-8-2 Conventional spoked
1937 4-8-2 Baldwin disc main only
1940 4-8-2 Baldwin disc main only
1941 4-8-2 Baldwin disc
B&O:
1944 2-8-8-4 Boxpok
D&RGW:
1937 4-6-6-4 Baldwin disc
1938 4-8-4 Baldwin disc
1942 4-6-6-4 Baldwin disc
L&HR:
1944 4-8-2 Boxpok (clone of 1941 B&M design with Baldwin disc)
L&N:
1942 2-8-4 Baldwin disc
1944 2-8-4 Boxpok
1949 2-8-4 Boxpok
MoPac:
1943 4-8-4 Boxpok (clone of the 1938 D&RGW design with Baldwin disc)
NdeM:
1946 4-8-4 Boxpok
RF&P:
1937 4-8-4 Baldwin disc
1937 4-8-4 Baldwin disc
1942 4-8-4 Baldwin disc
1945 4-8-4 Baldwin disc
StL-F:
1942 4-8-4 Baldwin disc
1943 4-8-4 Boxpok
WM:
1940 4-6-6-4 Baldwin disc
1941 4-6-6-4 Baldwin disc
1947 4-8-4 Boxpok
This I think shows that the “critical” years were 1943 and 1944.
Up to and including 1942, it seems that those roads who wanted Baldwin disc drivers on their Baldwin-built locomotives got what they wanted. That included two new designs for 1942, the L&N 2-8-4 (OK, it was a Baldwin version of the VS rather than a completely new design) and the Frisco 4-8-4.
Then in 1943 and 1944, roads whom one would have expected to buy Baldwin locomotives with Baldwin disc drivers instead had them with Boxpok drivers. These included the AT&SF, L&N and STL-SF. This strongly suggests that there was external influence at work, with the WPB as the prime suspect.
The MoPac and L&HR cases are less certain. Whilst they had clones of designs originally fitted with Baldwin disc drivers, it is also possible that those roads would have selected the Boxpok type had they had a free choice.
The B&O case is weak evidence. Its 1944 2-8-8-4 was a new design, so could have gone either way in respect of drivers had there been a free choice. The DM&IR 2-8-8-4 had Boxpok drivers, as did the later SP 4-8-8-2, although the SP had had a prior commitment to the Boxpok type.
Evidently Baldwin disc drivers were available again by 1945, as evidenced by the RF&P case. But that did not seem to have much influence post-WWII. WM chose Boxpok for its 4-8-4 despite previously being in the Baldwin disc camp, and it looks as if L&N, having had Boxpok on its 1944 batch probably as a forced choice, stayed with that for its 1949 batch of 2-8-4s. NdeM’s choice of Boxpok might have been to achieve standardization, as the other half of its 4-8-4 fleet came from Alco, who fitted the Boxpok type. Also, it was a clone of the NC&StL design, the later builds of which had Boxpok drivers. Still, that the Santa Fe was able to retrofit its 2900 class with Baldwin disc drivers (on the 4th driver set only) indicates that Baldwin was still producing the type post-WWII.
It might be worth looking at the huge SNCF 141R fleet in this regard, built I think by Alco, Baldwin, Lima and MLW in the years following WWII. Some of the later examples had disc drivers, Boxpoks from the pictures I have seen. But perhaps some of those built by Baldwin had Baldwin disc drivers. Editions Cabri I think did the definitive book on the 141R, but I have not seen it. Some, maybe all of the WP class 4-6-2s exported to India had disc drivers. From the pictures I can find, they were of the Boxpok type, but it seems possible that some of the Baldwin builds had Baldwin discs.
Cheers,
AT&SF:
1938 4-8-4 Baldwin disc
1938 2-10-4 Baldwin disc
1941 4-8-4 Baldwin disc.
1943 4-8-4 Boxpok
1944 2-10-4 Boxpok
B&M:
1935 4-8-2 Conventional spoked
1937 4-8-2 Baldwin disc main only
1940 4-8-2 Baldwin disc main only
1941 4-8-2 Baldwin disc
B&O:
1944 2-8-8-4 Boxpok
D&RGW:
1937 4-6-6-4 Baldwin disc
1938 4-8-4 Baldwin disc
1942 4-6-6-4 Baldwin disc
L&HR:
1944 4-8-2 Boxpok (clone of 1941 B&M design with Baldwin disc)
L&N:
1942 2-8-4 Baldwin disc
1944 2-8-4 Boxpok
1949 2-8-4 Boxpok
MoPac:
1943 4-8-4 Boxpok (clone of the 1938 D&RGW design with Baldwin disc)
NdeM:
1946 4-8-4 Boxpok
RF&P:
1937 4-8-4 Baldwin disc
1937 4-8-4 Baldwin disc
1942 4-8-4 Baldwin disc
1945 4-8-4 Baldwin disc
StL-F:
1942 4-8-4 Baldwin disc
1943 4-8-4 Boxpok
WM:
1940 4-6-6-4 Baldwin disc
1941 4-6-6-4 Baldwin disc
1947 4-8-4 Boxpok
This I think shows that the “critical” years were 1943 and 1944.
Up to and including 1942, it seems that those roads who wanted Baldwin disc drivers on their Baldwin-built locomotives got what they wanted. That included two new designs for 1942, the L&N 2-8-4 (OK, it was a Baldwin version of the VS rather than a completely new design) and the Frisco 4-8-4.
Then in 1943 and 1944, roads whom one would have expected to buy Baldwin locomotives with Baldwin disc drivers instead had them with Boxpok drivers. These included the AT&SF, L&N and STL-SF. This strongly suggests that there was external influence at work, with the WPB as the prime suspect.
The MoPac and L&HR cases are less certain. Whilst they had clones of designs originally fitted with Baldwin disc drivers, it is also possible that those roads would have selected the Boxpok type had they had a free choice.
The B&O case is weak evidence. Its 1944 2-8-8-4 was a new design, so could have gone either way in respect of drivers had there been a free choice. The DM&IR 2-8-8-4 had Boxpok drivers, as did the later SP 4-8-8-2, although the SP had had a prior commitment to the Boxpok type.
Evidently Baldwin disc drivers were available again by 1945, as evidenced by the RF&P case. But that did not seem to have much influence post-WWII. WM chose Boxpok for its 4-8-4 despite previously being in the Baldwin disc camp, and it looks as if L&N, having had Boxpok on its 1944 batch probably as a forced choice, stayed with that for its 1949 batch of 2-8-4s. NdeM’s choice of Boxpok might have been to achieve standardization, as the other half of its 4-8-4 fleet came from Alco, who fitted the Boxpok type. Also, it was a clone of the NC&StL design, the later builds of which had Boxpok drivers. Still, that the Santa Fe was able to retrofit its 2900 class with Baldwin disc drivers (on the 4th driver set only) indicates that Baldwin was still producing the type post-WWII.
It might be worth looking at the huge SNCF 141R fleet in this regard, built I think by Alco, Baldwin, Lima and MLW in the years following WWII. Some of the later examples had disc drivers, Boxpoks from the pictures I have seen. But perhaps some of those built by Baldwin had Baldwin disc drivers. Editions Cabri I think did the definitive book on the 141R, but I have not seen it. Some, maybe all of the WP class 4-6-2s exported to India had disc drivers. From the pictures I can find, they were of the Boxpok type, but it seems possible that some of the Baldwin builds had Baldwin discs.
Cheers,