UPRR is most likely Union Pacific Rail Road. It was probably filled (note the large hole) a screw plug inserted and then put on some stand laying on its side and drained through the smaller spigot. I couldn't tell you what it held, it could be any type of liquid from water to oil, railroads used a multitude of items back in the day as they were one of the largest industries in the country.

Regards, Jim

I collect gas pump salt and pepper shakers
and the plastic coin banks made by AVSCO.