A hand colored image of a hot pot engine at the Ensley furnaces. Card postmarked 1911, West End. Hot Pots had no fired boiler to produce steam. Two differetn methods were used. One was charging a heavily insulated vessel with live steam under pressure.

The other method was to charge a tank with compressed air. Compressed air was allowed to enter and rise through a vessel of hot water and steam under pressure. The hot air exited the vessel, entered the cylinders where the hot air expanded. As the high pressure in the water/steam tank lowered more water would flash into steam. Of course, the steam, water, and air would need replenishing periodically.

Postcard Birmingham is a work always in Progress by Warren Reed