Science Fair Project Encyclopedia
In rail terminology, a turntable is a device used to turn railroad rolling stock. When steam locomotives were still in wide use, the railroads needed a way to turn the locomotives around for return trips as their controls were not configured for extended periods of running in reverse. Turntables were also used to turn observation cars so that their windowed lounge ends could be oriented toward the rear of the train.
The turntable bridge (the part of the turntable that included the tracks and that swiveled to turn the equipment) could span anywhere from 30 to 120 feet, depending on the railroad's needs. Larger turntables were installed in the locomotive maintenance facilities for longer locomotives, while short line and narrow gauge railroads typically used smaller turntables as their equipment was smaller. Turntables as small as 10 feet in diameter have been installed in some industrial facilities where the equipment is small enough to be pushed one at a time by human power.
In engine maintenance facilities, a turntable was usually surrounded, in part (as in most cases) or in whole, by a roundhouse. It was more common for the roundhouse to only cover a portion of the land around a turntable but fully circular roundhouses exist, such as the preserved roundhouse that serves as the basis for the Baltimore and Ohio Railroad Museum in Baltimore, MD.
- Wye (railroad) - another way of turning whole trains.
- Traverser (railway)
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