I'm not sure if the law about burning witches ( heresy ) has been withdrawn so criticism of errors, or design flaws , has to be avoided.
However, I would suggest you carefully go through the dimensions of the drawing relating to clashing of the rotating parts with stationary objects over the full movement ( up and down ) of the axleboxe and complete 360deg rotation of parts.. Connecting rods fouling slide bars or the bottom end of the expansion link . Coupling rods hitting weighshafts , or crossheads !
Valve spindles not lining up with centre of expansion link , also eccentric rod connections well out of line with ' reality '.
On the drawing these will all ' look good', only a careful check placing the drawing dimensions onto squared paper will reveal the 'truth'.
Reading the write up of the day , end to end ,is useful and will include some errors , but not all !
Even if you find no errors , the time will have been well spent.