i had a look today.
looking at the vessel on the inlet before the steam valve the steam pipe comes in at the top down in the centre and the steam valve is
connected at the side near the top there is a good sized water drain at the bottom .in operating instructions it is referred to as the separator
that's whats on the bellis and morcomb engine that i see and run.orther engines i see have similar vessels on the steam line at the engine.
i would guess that worthington engine is similar not wonting water to get in the engine.just mounted above the engine they would bee in the way if matainance was required and if it was a crane it would have to be removed first.
John