oiler....that is ceratinly a unique aerial lay shaft & a very tidy steam plant 
Question....is that an auxiliary come home electric motor on the stdb lower side of the Hemmens steam engine?..............
....Derek
No but that would be a great idea! hmm

may have to think about adding one..
That is an electric water pump. I originally had a ram pump connected to the engine but it was dragging it down too much and erratic. I built a servo ram pump but it was too slow and it had to run all the time to keep up with the demands of the engine.
I found this 12V DC pump and it works great and was only $25 USD. It will pump 600ml a minute at 80 psi.