Postcard photo of what was once the largest locomotive in the world, owned by Southern Pacific.

The SP number can't be read but this is a Baldwin, as their round plate can be seen on the locomotive's left side.

This looks to be the MC-1 before it was converted to cab forward in the early 1920s.

(United States Card & Novelty Company, Chicago, Public domain, via Wikimedia Commons)



Southern Pacific Railroad's MC-1 class of steam locomotive consisted of two locomotives built by Baldwin Locomotive Works in April 1909. They are the first two locomotives converted by Southern Pacific (SP) to run as cab forward locomotives.

The first of these two, number 4000, entered service on May 26, 1909. It was rebuilt as a cab forward and reclassified as an MC-2 in June 1923. Another rebuild on June 4, 1931, "simpled" it with uniform cylinders and reclassified it as an AC-1. 4000 was scrapped on April 2, 1948. The second locomotive in this class, 4001, entered service on May 30, 1909. It was rebuilt as an MC-2 in April 1923, "simpled" on February 9, 1931, retired from active service on May 23, 1947, and scrapped on June 14, 1947, at SP's Sacramento shops.


A rare view of MC-1 No. 4000 under steam.

(Photographer unknown, via W. Lenheim Collection)


SP Class MC-1 Cab Forward Overview

Type and origin
Power type: Steam
Builder: Baldwin Locomotive Works
Serial number: 33340, 33341
Build date: April 1909
​• Whyte 2-8-8-2
Gauge: 4 ft 8+1⁄2 in (1,435 mm) standard gauge
Driver diameter: 57 in (1.448 m)
Adhesive weight: 394,150 lb (178,780 kg)
Locomotive weight: 425,900 lb (193,200 kg)
Boiler pressure: 200 psi (1.4 MPa)
High-pressure cylinder: 26 in × 30 in (660 mm × 762 mm)
Low-pressure cylinder: 40 in × 30 in (1,016 mm × 762 mm)
Performance figures
Tractive effort: 94,880 lbf (422.0 kN)
Operator: Southern Pacific Railroad
Class: MC-1
Number in class: 2
Numbers: 4000, 4001
First run: May 26, 1909
Retired: 1948
Disposition: scrapped