Actually, the Alco built 1111, which became NP's 2626 and was an A-1. There where A Class locomotives built for the N.P. previous to the Four Aces becoming an N.P. locomotive. The quantity of A Class locomotives is somewhat nebulous, the NPRHA website states there where two A class locos, #s 2610 and 2611 that where built, and at another location at the website it states there where 12, #s 2600 to 2611. Generally a class of locomotives started with the beginning number in a series, this makes me think there where probably the 12 numbers and not only two. Information at the website indicates that the A Class locos were built in 1926. The Four Aces was build by Alco's Schenectady plant in 1930 as a demonstrator for replacing roller bearings. So, the 2626 was not the first Northern purchased by the Northern Pacific. The Northern Pacific actually took delivery of the Four Aces in August of 1931 and the Northern Design had been around since 1926. The N.P.'s 2626 was the only A-1 Class locomotive.