So I was scanning one of my favorite photo collections, J. Parker Lamb, https://railphoto-art.org/collections/lamb/group-four/ , and found this pic of a diesel, GM&O #1900. What is that?
The Gulf Mobile & Ohio diesel roster lists it as a 4-S built by Ingalls Shipbuilding. The GM&O merged with the Illinois Central in 1972 and became the Illinois Central Gulf. But, the ICG roster does not appear to list the 4-S.
So I went to Ingalls Shipbuilding to find info on the 4-S. …And here was the first pic – GM&O #1900!
Turns out that the 4-S was an experimental locomotive built in 1946. It never appears on the ICG roster because it was retired in 1966.
The diesel electric prime mover was based on a marine engine built by Superior Engines and Compressors. The 4-S was tested by several railroads including the L&N, SAL, and Southern. But lack of interest in the 4-S along with Ingall’s entire projected diesel loco line left the one test 4-S as the only one Ingalls built. It was sold to the GM&O and was considered a tough workhorse of an engine. Even after a bad derailment left the unit inverted, and there were no replacement parts available from Ingalls (they had gotten out of the RR loco business when no one showed interest in their line), GM&O rebuilt it and continued its use. It was eventually scrapped a year after retirement, 1967.
The GM&O used #1900 for a variety of purposes. It was spotted pulling a 3 or 4 car passenger train at one point. When it overturned, it was pulling a work train. According to the GM&O Historic Society, reported spottings of #1900 were made all over the GM&O.