@Steve-- The large steel plates, to which I believe you are referring as load bearing, are not. These are spring-loaded to slide against the bottom of the cab floor, and serve to seal the air flow ducts cooling the 12 motors. I think that the vertical load is taken to the subframe at the center pivots, in the usual manner. Notice that the cab is on 4 stands at the ends of the two cross beams at these points.
I believe that you will find that these points are just a bit further outboard of the outermost drive axle at each end. Or, about 4/9ths outboard along a line joining the center driving axle with the center of the pilot truck. This is based on the pilot axles (2) each carrying 2/3d's the weight carried by each of driving axles (3). Actual weights are not so uniform and the actual calculation is more complex. This depends also on installed equipment, particularly the steam boiler, but I think all the pivot points were the same.
I notice a loading pad on the nearest frame (in pix) outboard of the wheels. Can't tell is this in a tipping roller or a flat loading pad of low-friction material. It is inline with the center pin location as described above.
@Steve-- There is no lateral motion in any of the driving axles of a GG-1, including the center one. Pennsy had their own standards and did not follow AREA (as it was then) standards. In particular, the driving wheels were flat (IIRC), and ran in a tighter gauge of 4'-8 1/4" on tangent, with gauge widened on curve as necessary (see book written by a track foreman of Pennsy, found in Enoch Pratt Free Library Baltimore nearly 65 years ago; still there last time I was).
IIRC, Amtrak in fitting out Ivy City to service GG1s in their waning days, had two drop tables which could be used to remove GG1 driver wheelsets for wheel truing. So profile wear on passenger power received a lot of attention. Flat treads reduce impact in passing through open frogs.
In general-- I looked at the MTH pantographs. They are against the inside top of the Lionel clear cases at a scale 21-feet over the rail head. The interior angle between the lower and upper frame is about 45-degrees at this height. I think the appearance would be slightly better at the high-speed height of 22 scale feet. It appears these would reach the yard lead height of 26-feet without losing spring pressure against the wire, but I did not have time to take the case down and measure this. On the Lionel, I have both pans set well below a less tall glass case, one at 18-feet with 30-degree internal angle and the other at 17-feet. They look quite operational in holding the pans level. Of course, the wire following is not possible for varying heights, although that height can be chosen. But there is no need to worry about coming out from under the wire horizontally.
--Frank
