dynamic brakes were included). The radiator fans were recessed within the carbody, and arranged in two pairs, one near each end of the locomotive. Later units have the fans grouped together, and their shrouding extended atop the roof. The overhangs of the body past the trucks differ in the FT compared to later units. The B-units of FTs ordered in semi-permanently coupled A-B sets, and those with couplers on both ends, have a large overhang on one end (the coupler-equipped end on the paired units) featured on no other EMD B-units. This is not present on the B-units in semi-permanently coupled A-B-A sets, which were called FTSB units (for Short Booster). At other locations, except the cab front, the FT units have less of an overhang than later units; the trucks appear to be right at the ends of the car bodies. As with other early cab units - but unlike "hood" type locomotives - the F (and E) series used the body as a structural element, similar to a truss bridge. Most of EMD's newer passenger locomotives have a non-structural “cowl” type body built on an underframe derived from freight designs. Wartime restrictions During World War II, locomotive production was regulated by the War Production Board. First priority for the diesel prime movers' manufacturing capability, as well as the materials used in the fabrication and assembly of the engines, electric generators and traction motors was for military use. Steam locomotives could be built with fewer precious materials, and with less conflict with military needs. It was also opportune for eastern railroads to stick with coal-fired steam power while petroleum distribution to the east coast was disrupted in early days of the US war effort. The traditional locomotive builders were prohibited from developing or building diesel road locomotives until early 1945, with the exception of a few dual-service ALCO DL-109s for the New Haven Railway. EMD, however, was purely a diesel builder, and therefore was allowed to build diesel freight locomotives, as consistent with fulfilling Navy needs for their 567 engines. The WPB assigned the FTs to the railroads it deemed most able to benefit from the new locomotives. Santa Fe received by far the largest allocation, given its heavy war traffic and the difficulty and expense of providing water for steam locomotives on its long desert stretches. Were it not for the wartime restrictions, many more FTs would have