Erie Ball steam engine, built in Pittsburgh in early 1900s. This engine or its twin has run nearly continuously since the plant was built. They drive huge Roots induction blowers for Erie Coke, a very modest coking operation that supplies foundry and farrier coke more than steel mill coke.

Almost certainly the only steam-powered coke works left in the USA ca. 2000.

The guys had an engine down when I was there and they weren't really in the mood for visitors, so I only got a few marginal pics.