I hate to just put up technical jargon - so it's time for a few more pictures, as always from actual sources. Let's use some of the early GE sales brochures.
At left is a small shot included in the 1960 brochure announcing the U25B locomotive. This shot is of unit 751 coupled to what appears to be an ERIE F3B, obviously during the testing period that preceded announcement of the model. Note the original configuration with no front rails or platform. GE 751 and 752 carried the designation "FG-24" under their road numbers during this period, indicating "Freight, GE, 2400 HP." That FG-24 label is clear in another detail shot we won't show here, which was meant to show under-cab compartment details.
Here are GE 751 and 752 together, after modification and during the period in which they were demonstrating as U25B units, prior to construction of the four-unit set of production U25B demonstrators, units 753 through 756, in early 1961.
At left is a great color shot included in a large binder that GE issued to advertise the U25B, showing the lowest numbered unit of the 1961 U25B demonstrator set. GE seems to have used this shot with at least one other airbrushed background. This large binder includes a sales brochure, a specification booklet, and several transcripts of technical lectures delivered concerning the U25B and its development. In the sales brochure is an interesting illustration, shown next.
This shot seems to depict a control stand and instrument layout between two of the previously shown ones (see the older post on GE control stands.) Judging by the layout of switches, the addition of a power limit switch but the placement of the ammeter on the bulkhead instead of in the instrument panel below the front window, it would appear that this exact control stand and instrument layout would apply perhaps only to the four-unit demonstrator set 753-756 considering that the operating manual shows the layout with ammeter in the front panel. This might be splitting hairs, but it's sensible guesswork and provides an interesting in-depth addition to our study of early GE control stand layouts.
Stay tuned to our blog for MANY more materials from all of the locomotive builders.