The Argentine Great Western Railway, or Gran Oeste Argentino, received ten 2-6-2T tank locomotive from Robert Stephenson & Co. in 1907. These carried the works numbers 3272 to 3281 and the running numbers 311 to 320. Later they were renumbered 901 to 910. Designed by Charles H. Fox, they had outside cylinders and Walschaert valve gear. The side tanks with a total capacity of 2,000 imperial gallons were relatively high and might have obstructed the view forward.