Southern Pacific 4-8-2 No. 4324 belonged to the Mt-1 class, outshopped in 1923-24 by ALCo's Schenectady Works. This unprovenanced view, saved from an Internet site that has since been discontinued, depicts No. 4324 with the later modifications applied to most members of the Mt class: the skyline casing, the main disc driver, and where not original, the multiple-bearing crosshead. These engines had an evaporative heating surface of 4561 square feet, a superheating surface of 1162 square feet, and a 76-square-foot grate area.