Morning blow-down. With Locomotive #108 positioned just short of the the wooden trestle at the north end of the Hill City Yard, Black Hills Central Engineer Cesar and his fireman open the blow-down valves on #108 to rid the mud-ring section of the firebox of any loose sediment and contaminants. Instantly, super-heated water is ejected out of both sides of the locomotive at boiler pressure (about 190 PSI), and instantly flashes to steam. The process is loud and typically attracts spectators, some of whom will get a bit wet if they're standing downwind. This blow-down procedure is executed before the first run every day, and is repeated at least once during each run, typically in a secluded section of the line. With the procedure complete, the crew will back the locomotive up to the water tank near the station to fill the big saddle tank, before coupling on to their train.
