Kansas City Southern EMD F3 units #30A/B were used on the Southern Belle passenger train, running between Kansas City, Missouri and Shreveport, Louisiana. This image was recorded in LaGrange, Illinois during their delivery in November of 1947. It was scanned from a Vanishing Vistas postcard that I have.

In the early days of diesel locomotives, it was common to semi-permanently couple multiple units together with drawbars to achieve a desired total horsepower. As I understand, at this point in time union rules required a crew on each individual locomotive. This drawbar arrangement allowed multiple locomotives to count as one unit, thus allowing the use of a single crew. This locomotive (consist) was numbered 30. To identify the individual units within the consist, a suffix of A or B (or C, etc. as needed) was added to the number on each unit. In the case of this consist, we have 30A (the lead unit) and 30B.

Note the black paint extending up onto the roof at the rear of the second unit. This was done in an effort to “blend” the arrangement of paint colors on the locomotives to the arrangement of the colors on the passenger cars. Below is a post card showing the result.

At some point the union rules were changed and the units were separated and had the drawbar replaced with conventional couplers. This made maintenance and the mixing/matching of units much easier. #30A was eventually renumbered to 4050. And that unit was eventually rebuilt as a slug in 1981.