Those are fairly obvious points from the cross-section. Old stories in Trains about the F-Ms did mention issues with the upper crankcase and power coupling, that were fixed over time as Alco did with it's early designs. Lifting out the crankshaft for heavy work was also an issue, but it was a shop issue not an operating one. In early applications, the cooling of F-M engines was also an issue - needed large radiators and a lot of water; in submarines that was less of a problem because there was a whole ocean to cool them with. My vague recollection of the Peninsula units (a few rides as pre- and teenager) was that, like GMs, they didn't smoke too badly - nothing like Alcos of the time.

On the whole, though, they seemed to work well enough; at least SP bought some, and the Trainmasters did well in Peninsula Commute service. But of course they were a small builders in the early part of the diesel era, and couldn't effectively compete with GM & Alco (later GM & GE) for volume and development. Do have to given them credit for producing the first "high horsepower" hood units (Trainmaster) with 2400hp back when GM needed 2 units (or 2 engines in a E unit) for that.