My guess is that the actual FRAME may not be higher than usual: the walkway is raised above the frame level. I recall reading somewhere that this was done with a view to safety (or a particular interpretation of the FRA's (? FRA? When Trainmaster wa designed? Maybe some earlier regulatory agency like the ICC?)safety regulations: it eliminates steps on the external walkways of the unit. Note that the cab cloor of other makes of hood unit is above the walkway, so there is a step: on the Trainmaster the cab door is at walkway level. ... I think, if I were an engineman who had to go outside the cab at night in freezing rain to go back and re-set something on the third unit of the consist, I might appreciate this feature.
At which point the "squat" appearance of the food is partially explained: there just isn't as much height of hood aboe the walkway as on other units. Part: the FM hood is also, I think, wider than some, and I'm not sure why that is. I know the FM prime mover is tall: is it also wide?