Class A-2a (Locobase 51)

Data from Walter A Lucas, Popular Picture and Plan Book of Railroad Cars and Locomotives (New York: Simmons-Boardman Publishing Corp, 1951), p. 20; see also Richard Leonard's online rail archive entry on the the P&LEs at [], last accessed 1 July 2017. (Many thanks to Chris Hohl for his 22 September 2017 email reporting unlikely boiler pressure values for 177 entries. A Locobase macro caused the error .)

The NYC's last steam locomotives delivered and the last from Alco's Schenectady Works, these went to the Pittsburgh and Lake Erie. Richard Leonard noted that unlike most 2-8-4s, these engines had relatively small 63" drivers.

They were retired in 1957.

Class A1a/b (Locobase 46)

Data from table in Locomotive Cyclopedia of 1930. See also "Lima Builds 2-8-4 Type Locomotive", Railway Age, Volume 78, No 22 (2 May 1925), pp. 1077-1082 for hyper-detailed description; and F A Butler, "Tests of 2-8-4 Locomotive on B&A", Railway Age, Volume 79, No 11 (12 September 1925), pp. 467-471; and William Withuhn, American Steam Locomotives: Design and Development: 1880-1960 (Bloomington, IN: Indiana University Press and Pflugerville, TX: Railway & Locomotive Historical Society, 2019), pp. 216.221. (Many thanks to Chris Hohl for his 22 September 2017 email reporting unlikely boiler pressure values for 177 entries. A Locobase macro caused the error .) Works numbers were 6979-7003 in February 1926 and after as well as 7192-7211 in December.

Boiler had Elesco feedwater heater, valve motion had limited cutoff. Boston and Maine T-1 class (Locobase 47) and Illinois Central #7000 class (Locobase 48) were very similar and built at approximately the same time. In addition to the performance improvements described below, RA's May 1925 report pointed to other features such as "a marked improvement in ash pan design", cast-steel cylinders saving 4,000 lb (1,814 kg) in weight, a simple port arrangement allowing an unbalanced cutoff at starting which smoothed the starting torque curve, and an articulated main rod that applied loads to two outside crankpins instead of one. (Butler commented in September that the two pins showed equal wear, but more time in service would be needed to confirm the value of the inovation.)

A few months after the first engines entered B&A service, Superintendent of Motive Power and Rolling Stock F A Butler reported on initial findings in the Railway Age. A key average reported was the 52.66 lb/square foot/hour (257.11 kg/sq m) measured on the grate. Butler credited the large firebox and the Type E superheater's gas area with achieving 8.13 lb (3.69 kg) of water evaporated per lb of coal as fired (dry coal equivalent was 11.37 lb). Running with an average cut-off of 43.7% generated 1,923.7 horsepower and maximum cylinder horsepower of 3,675. (Best starting tractive effort was achieved when the maximum cut-off was set to 60%.)

Butler compared the A-1s with Mikado 190 in a run on 14 April 1925. The 2-8-2 hauled 46 cars weighing 1,691 tons, the 2-8-4 trailed 54 cars loaded to 2,296 tons. Both trains ran without delays, wrote Butler, with the A-1 overtaking the 190 during the run. During the run, the A-1 averaged 4,00-6,000 lb of coal fired per hour and a dynamometer horsepower measured at between 1,200-1,750 hp. Even during "very light work", the grate delivered proper combustion and firing rates as low as 41 lb (18.6 kg)/sq ft/hour.

The 190 never burned less than 5,000 lb per hour and at some points consumed as much as 7,200 lb per hour. Where the two engines had similar firing rates, the A-1 showed an average reduction of 23.5-33%.

Butler added that the articulated trailing truck "seemed to adapt itself very well to the track condtions. The engine rode steadily up to the highest operating speeds which the service required.

Later A-1c (1445-1454) -- see Locobase 3172 -- carried 78 2 1/4-in tubes, concealed Coffin feedwater heaters, and the firebox was fitted with 149 sq ft (13.85 sq m) of thermic syphons.

Retired in 1949, after which 1423 and 1434 were sold in 1950 to the Tennessee, Alabama & Georgia as their 601-602. The TAG Line operated the pair for about two years before retiring them in October 1952.

Class A1c (Locobase 3172)

Data from NYC 1 - 1944 Locomotive Diagrams supplied in April 2005 by Allen Stanley from his extensive Rail Data Exchange. (Thanks to Chris Hohl for his 3 April 2015 email correcting the valve gear and his 12 March 2020 email noting an inconsistent road number format.) Works numbers were 7556-7565 in August 1930.

This was the last batch of ten Berkshires built for the B&A. Compared to the A-1a/b of a few years earlier (Locobase 46), these had fewer 2 1/4" tubes (74 vs 90), concealed Coffin feedwater heaters vs Elescos, and the arch tubes in the firebox were removed in favor of another thermic syphon, which raised their total area to 149 sq ft (13.85 sq m). They still used 14" (356 mm) piston valves, which were actuated by Baker valve gear.

Retired in 1949.