Starting in 1905, the Southern Pacific and its subsidiaries bought a large number of Harriman Common Standard Consolidations. The SP itself got 169 and the Texas & Louisiana 50, both calling them class C-9. They had a relatively small oil-fired firebox, but the oil was atomized outside of the firebox. According to Mexican Fuel Oil, this saved some oil and made cleaning easier. Starting in 1922, most of these locomotives were superheated and got a larger tender.