One of four Main Engines. From Nils Pearson's photos circa 1952.
Each of the four main engines had one generator attached to it. The engines turned the generators to create electricity to send to the four electric motors in the Motor Room which were attached to the Reduction Gear which powered the shaft and prop.
Nils is checking an injector rack on a cylinder head in this photos from Nils Pearson's photos circa 1952.
This photo shows the size of the Main Engines with L to R Leech, Watson and Pearson. Circa 1952 from Nils Pearson's photos.