Skip to main content


SS Badger Carferry
Society: ASME Main Category: Mechanical Sub Category: Water Transportation Era: 1950-1959 DateCreated: 1952 Lake Michigan Ludington State: MI Zip: 49431 Country: USA Website: Creator: Christy Corporation, Skinner Engine Company

The two 3,500-hp steeple compound Unaflow steam engines powering the S.S. Badger represent one of the last types of reciprocating marine steam engines. Built by the Skinner Engine Company, most Unaflow engines are single expansion. These feature tandem high- and low-pressure cylinders separated by a common head. The Badger's four Foster-Wheeler Type D marine boilers, which supply 470-psig steam to the engines, are among the last coal-fired marine boilers built. 

Image Credit: Courtesy Flickr/ssbadger (CC BY 2.0) Image Caption: SS Badger Carferry Era_date_from: 1952
Gravimetric Coal Feeder
Society: ASME Main Category: Mechanical Sub Category: Manufacturing Era: 1950-1959 DateCreated: 1957 Stock Equipment Plant Chagrin Falls State: OH Zip: Country: USA Website: Creator: Stock, Arthur, Hardgrove, Ralph

A variety of mechanical feeders, including drag-chain conveyors and rotary pocket feeders, historically have been used to volumetrically control the flow of fuel to coal pulverizers on power generators. Most power generation in the United States has relied on burning fossil fuels in steam boilers, with coal as the fuel of choice. By the 1920s, pulverized-firing (the burning in suspension of finely ground coal particles) evolved as means to more complete fuel combustion and higher system efficiencies and facilitated the use of larger boilers.

Image Credit: Image Caption: Drawing from patent documents for Gravimetric Coal Feeder. Era_date_from: 1957
Society: ASME Main Category: Mechanical, Electric Sub Category: Steam Era: 1900-1909 DateCreated: 1906 6605 13th Avenue South Seattle State: WA Zip: 98108 Country: USA Website: Creator: Stone and Webster, Gilbreth, Frank
The Georgetown Steam Plant, a surprisingly complete and operable steam power plant after a career of nearly seventy-five years, was built in the early 1900s when Seattle's inexpensive hydroelectric power attracted manufacturers. Much of the power produced at this plant operated the streetcars.
Image Credit: Courtesy Flickr/wneuetc (CC BY-ND 2.0) Image Caption: Georgetown Steam Plant Era_date_from: 1906
Subscribe to Coal-Fired

We hope you enjoyed this essay.

Please support this 70-year tradition of trusted historical writing and the volunteers that sustain it with a donation to American Heritage.


Stay informed - subscribe to our newsletter.
The subscriber's email address.