• The Locomotive Booster Engine, Revisited

  • Discussion of steam locomotives from all manufacturers and railroads
Discussion of steam locomotives from all manufacturers and railroads

Moderators: Typewriters, slide rules

  by Fan Railer
 
Rather than necropost on a thread that hasn't been touched in over a decade, I figured I'd start a new one. In the past, most of the information I was able to find on their application and performance was limited to indirect sources, such as the specification cards of various locomotives, which stated booster tractive effort in addition to main engine tractive effort. The operating / maintenance manuals from Franklin were slightly more detailed, but even for a direct source, it lacked the kind of detailed info I was after.

My recent digging around in the archives of Railway Mechanical Engineer magazine issues unearthed some really neat articles concerning both the Type C and Type E boosters offered by the Franklin Railway Supply Company. The October 1922 issue features dynamometer test results for the Type C booster, while the September 1944 issue features dynamometer test results for the Type E. Additionally, the July 1929 issue introduces the equation used for approximating booster tractive effort.

Included as part of the dynamometer test reports are detailed specifications for the booster, as well as available gear ratios and associated operating speed limitations. In short, the Type C booster came with one gear ratio of 2.571, and could be cut in up to 12 mph and operated up to 21 mph or so. The Type E high speed booster came with three gear ratios; 2.71, 2.25, or 2.00, and with the highest ratio could be cut in up to 15 mph and operated up to 25 mph; the lowest ratio yielded a maximum cut in speed of 22 mph and operating speed of 35 mph.

Articles:
https://archive.org/details/sim_railway ... ew=theater
https://archive.org/details/sim_railway ... ew=theater
https://archive.org/details/sim_railway ... ew=theater

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This data makes it possible to reverse engineer booster operating parameters for existing locomotives; you just have to know the rated tractive effort and the trailing wheel diameter.