Tim,
Before Baldwin started producing them, ALCO had built at least 90 of the MacArthur 2-8-2s: USA 3000 to 3029, and USA 130 to 189. ALCO continued to produce MacArthurs when the order for 60 more was given to Baldwin in 1942. I'm guessing that sequence numbers were assigned based on orders and construction numbers were assigned based on completion. It's possible that when Baldwin took order #42301 for the 20 42" gauge loks for Queensland, and 40 meter gauge loks for India, ALCO had produced 113 MacArthurs by that time, so as far as Baldwin's numbering system was concerned 114 would be the next lok in the MacArthur design sequence. Beginning with 114, the sequence numbers are consecutive through the 20 Qld loks, and continue in sequence for 5 meter gauge loks for India, seq #s 134 to 138, then the sequence numbers 139 to 149 are for the 11 36" WP&YR loks.
So far I've seen no evidence to support the claim that they were built first as meter gauge then disassembled and converted to 36" gauge. Why would they do this with wartime production demands? To me it makes more sense that they were 5 loks into the order for the 40 meter gauge loks for India when the word came to Baldwin to stop production of meter gauge and make 11 36" gauge for the WP&YR, then resume meter gauge production. They had already worked out the shims and spacers to convert the basic 42" MacArthur design to meter gauge, so different shims and spacers for 36" wouldn't be a problem and production would continue without interruption. The sequence numbering supports this and it would have made more sense to do it this way to meet the wartime maximum production requirements. Sequence number 150 through sequence number 173 were the remaining meter gauge loks for India to complete order #42301.
USA#s 250 to 256 had already been assigned to the 7 K-28s already operating on the WP&YR by that time.
Mike
