Southern Pacific class MC-4

Southern Pacific class MC-4
Type and origin
Power type Steam
Builder Baldwin Locomotive Works
Serial number 36490-36493, 36524-36527, 36614-36616, 36634
Build date April–May 1911
Specifications
Configuration 2-8-8-2
Gauge 4 ft 8 1⁄2 in (1,435 mm)
Driver diameter 57 in (1,448 mm)
Weight on drivers 398,500 lb (180,800 kg)
Locomotive weight 432,600 lb (196,200 kg)
Boiler pressure 200 psi (1.4 MPa)
High-pressure
cylinder size		 26 in × 30 in (660 mm × 762 mm)
Low-pressure
cylinder size		 40 in × 30 in (1,016 mm × 762 mm)
Performance figures
Tractive effort 85,040 lbf (378.28 kN)
Career
Operator(s) Southern Pacific Railroad
Class MC-4
Number(s) 4017 – 4028
First run July 21, 1911
Retired 1947 – 1948
Disposition scrapped

Southern Pacific Railroad's MC-4 class of steam locomotive was the second class ordered and built as cab forward locomotives. Southern Pacific (SP) found the MC-2 class as sufficient enough for a proof-of-concept for cab forward locomotives and sought to continue with now tested designs.

In service, SP found that the locomotives were a little too slow for the traffic needs. By 1930, all of the MC-4 class had been "simpled" to use uniform size cylinders and feedwater heaters were installed to address the issue. They were then reclassified as AC-2 locomotives. As rebuilt, the locomotives continued in service through the end of World War II.

References