I should have added that if a driver was out of quarter, it could also be possible that the rod pin's holes in the rod ends have become elongated. If they fit too loosely, the mechanism can bind even if all drivers are in quarter.
Again, it might be possible to bore out elongated rod holes and refit them with brass tube bushings. But getting the rod pin holes to the exact spacing needed is a machinist's art. And, you have only one shot to get it right! Replacement rods are another part not easily found now.
FWIW: The special B&O P-7 class "Presidential" paint job of green with gold and red striping on B&O 2024 was for its status as the dedicated locomotive for B&O President Daniel Willard's inspection train from 1925 to about 1930. Depression era austerity put the 2024 back into pool service in black paint. Willard's inspection train (usually a coach/baggage combine, a diner, a 12 section /1 drawing room Pullman and B&O office car "Maryland") was from then on drawn by a pool service locomotive.
S. Islander
