Only 10 ESM Freight Cars??? 
The ten consists of one G26 PRRck gon, one Sovereign G26 PRRck gon, one Sovereign F25 PRRck well car, one Magor 1950 BAR SoM XiH boxcar, one PC&F 1953 BAR SoM XIH boxcar, and five NH SoM XIH boxcars. Technically, out of the pool of period-appropriate ESM stock, even ten is too many for 1956. Proportionally, I should have far fewer NH SoM XIH boxcars, but they look too cool together not to have them all.
For my GHQ conversion I sliced off the lower flange on the lowered section, and that let me use the small CAPY LT WT LOAD LMT data block from the MS NH freight car data. Otherwise it won't fit. I used a picture from Liljestrand's book about Rolling Stock of New England for my model.
AFAIK the lower flange on should remain. The vertical ribs are the only required body modification. LT WT was separate from CAPY and LD LMT on the deco scheme I used.
My two could be lower to the rails also. I got it right with the two bigger cars kitbashed from the MTL model.
