RE Tom Nelligan (6 posts up):
" The EP-5 electrics grew out of freight service demo units that GE had built for the PRR in the early 1950s"
I don't think that's quite right. The cosmetic design of the cabs is similar, but the EP-5 was not, in it fundamentals, a derivative of the demonstrators built earlier for the PRR (and GN). The demonstrators were straight-AC locomotives (so: in principle the same sort of beast as PRR's earlier AC motors, e.g. the P5A and GG-1), whereas the EP-5 was a rectifier unit with DC traction motors (so: in principle more the sort of critter represented by PRR's later E-44 freighters). What IS the case is that GE, at the time, was still interested in building straight-electric locomotives, and was prepared to build rectifier-equipped units with DC motors: the EP-5 was similar in its electrical engineering to the slightly later units built for the Virginian (which ultimately became New Haven units and finally PC E-33). The New Haven's special circumstances (heavy short-distance passenger runs, with a change from third-rail DC to overhead AC power en route) guaranteed that ANYTHING they ordered would involve special engineering.
---
Baldwin, when they built the dual-cab units for CNJ, was very much playing catch-up ball in the diesel market, and probably willing to do unorthodox things to land an order. None of the other American diesel builders seem ever to have offered a dual-cab model domestically (though EMD, Alco, and GE have all produced dual-cab locomotives for use outside North America). Note that very few non-North American railways operate trains of the size common in North America: for North American use, multiple-unit diesel consists were standard from the end of the 1930s. Alco, EMD, Baldwin and FM all built "dual-cab" LOCOMOTIVES… in AA, ABA, and ABBA configurations!