Aerial photos do make clear that the power plant constructed around 1930 had its own
siding for coal delivery via train. Hopper cars were pushed onto a trestle so their
coal could be unloaded via gravity (see photo linked below). Though often called
"power plants" private facilities like this typically generated not electricity but
rather steam for heating.
Before the 20th Century it was common for each building of a group to have its own
heat source, perhaps a small coal furnance or even wood fireplaces. During the early
20th Century a centralized power plant like this one with distributed steam was deemed
easier to maintain than many smaller, scattered systems. However what is old is new
again: by the 21st Century many of these plants have been shuttered as buildings have
returned to the individual heat source approach via reliable and efficient heat pumps
that, as a bonus, can shift over to cooling during the summer.
very similar view in 1966,