A railway turntable is a device for turning railroad rolling stock. When steam locomotives were still in wide use, many railroads needed a way to turn the locomotives around for return trips as their controls were often not configured for extended periods of running in reverse and in many locomotives the top speed was lower in reverse motion. Turntables were also used to turn observation cars so that their windowed lounge ends faced toward the rear of the train.[1]
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Most turntables consisted of a circular pit in which the bridge rotated. The outer ends of the bridge were typically supported by a rail running around the floor of the pit, supplementing the central pivot. The turntable bridge (the part of the turntable that included the tracks and that swivelled to turn the equipment) could span anywhere from 6 to 120 feet (1.8 to 36.6 m), 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 6 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 or horse power.
Turntables will have a positive locking mechanism to prevent undesired rotation and to align the bridge rails with the exit track. Rotation of the bridge could be accomplished manually (either by brute force or with a windlass system) by an external power source or by the braking system of the locomotive itself, though this required a locomotive to be on the table for it to be rotated.
In engine maintenance facilities, a turntable was usually surrounded, in part 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 these preserved roundhouses:
Due to the asymmetric design of many locomotives, turntables still in use are more common in North America than in Europe, where locomotive design favors configurations with a controller cabin on both ends or in the middle. In San Francisco, USA, the Powell cable car line uses turntables at the end of the routes, since the cable cars have operating controls at only one end of the car.
In Britain, where steam hauled trains generally have vacuum operated brakes, it was quite common for turntables to be operated by vacuum motors worked from the locomotive's vacuum ejector or pump via a flexible hose or pipe although a few manually and electrically operated examples exist.
Several working examples remain; many on Heritage railways in Great Britain, and also in the United States. Examples include:
In the United States, when deciding liability for turntable accidents, most state courts followed the precedent set by the United States Supreme Court in Sioux City & Pacific R.R. v. Stout (1873).[2] In that case, a six-year-old child was playing on the unguarded, unfenced turntable when his friends began turning it. While attempting to get off, his foot became stuck and was crushed. The Court held that although the railroad was not bound by the same duty of care to strangers as it was to its passengers, it would be liable for negligence "if from the evidence given it might justly be inferred by the jury that the defendant, in the construction, location, management, or condition of its machine has omitted that care and attention to prevent the occurrence of accidents which prudent and careful men ordinarily bestow."[3]
In the case of Chicago B. & Q.R. Co. v. Krayenbuhl (1902), a four year old child was playing on an unlocked, unguarded railroad turntable. Other children set the turntable in motion, and it severed the ankle of the young child. The child's family sued the railroad company on a theory of negligence and won at trial. The Nebraska Supreme Court held that the railroad company may have been liable for negligence after considering the "character and location of the premises, the purpose for which they are used, the probability of injury therefrom, the precautions necessary to prevent such injury, and the relations such precautions bear to the beneficial use of the premises." However, the Supreme Court reversed the trial court's decision based on an improper jury instruction as to the evidence.[4]
Accidents to locomotives sometimes occurred. For example, if a locomotive failed to stop (when the turntable was incorrectly set) it might fall into the turntable pit.
Stations housing large numbers of engines may have more than one turntable:
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