by Allen Hazen
I think I have been told what the difference between the J1 and the J1a was, perhaps even on this forum, but I can't remember and can't find a string that looks relevant. Can someone tell me just how the two sub variants of PRR 2-10-4 differed?
It's NOT a matter of one having a one-piece cast frame and the other not: I think all J1a had one-piece frames AND some (but not all) J1 did, too. I found one internet source that said that the J1 were built in 1942-1944, but that all the J1a were built in 1943. This suggests that the J1a was a response to temporary (War Production Board mandated?) unavailability of some components or materials.
HELP! This is bugging me...
It's NOT a matter of one having a one-piece cast frame and the other not: I think all J1a had one-piece frames AND some (but not all) J1 did, too. I found one internet source that said that the J1 were built in 1942-1944, but that all the J1a were built in 1943. This suggests that the J1a was a response to temporary (War Production Board mandated?) unavailability of some components or materials.
HELP! This is bugging me...