my ESPEE MODELERS ARCHIVE

California's Railroad to the U.S. 1861 - 1996

Southern Pacific ALCo S4

64 units delivered

54 units to SP

3 images from various angles of #1831 at various locations from Bob Dengler

The ALCo S-4 was the post-war version of the ALCo S-2, outwardly very similar to the S-2, it rode on standard AAR 'B' type trucks. Deliveries started in 1951 and went through to 1955.

Differences appear to be mininmal, the exhaust stack seems to be similar to the Atlas model on lower numbered units, later units seem to have a rectangular style in the photo's at the top of the page. This may have been due to a change in turbocharger technology...

The cabs appear to be all welded, as against the early/late S-2's, which came riveted and welded.

These S-4's were found all over the system in general yard service from Oakland, CA. to Dallas, TX.

One S4 has been preserved in Tiger Striped (SP #1474) at the Orange Empire Museum, Perris Ca.

References:

• MR Diesel Cyclopedia Vol.2 page 40 - Plans for an S2.
• SP Dieselization by John Bonds Garmany - Chapter 6, Pre-war switchers.
• Extra 2200 South 1976 Roster Part I, Issue 54, Oct/Nov/Dec 1975
• Extra 2200 South 1976 Roster Part III, Issue 56, Apr/May/Jun 1976
• Southern Pacific Motive Power Annual 1967-69 - page 7.
• Southern Pacific Motive Power Annual 1980 - pages 18-25.