While watching a train pass by, you might wonder how do trains turn around? Clearly if they are going somewhere, they will have to come back, maybe along the same route.
The short answer is that trains usually don’t turn around! After all, locomotives can run backwards and freight cars usually run equally well in either direction. Steam engines… not so easily.
However, there are times when a locomotive, a snow plow, a freight car or a passenger car has to be turned. There are several ways to turn a train car or locomotive:
- A turntable
- A wye
- A loop track
Let’s look at each option.
Turntables
A turntable is basically a round platform with a section of track that can be rotated through a complete circle. Usually there are several tracks radiating away from the turntable, and often turntables were placed outside engine roundhouses.
A turntable’s diameter must be large enough to fit the longest engine or car that needs to be turned. For example, the turntable at the Toronto John Street Roundhouse is 120 feet wide, one of the largest built in Canada and capable of turning the longest steam engines that were in use in Canada. However, even this turntable is not long enough to turn a Union Pacific “Big Boy” steam locomotive with its tender.
Turntables can be operated using compressed air or they can be turned by hand. A locomotive can supply the compressed air if necessary. The hand turned ones are often called “Armstrong” turntables because you need strong arms to turn them!
A turntable is basically a bridge structure balanced on a central pivot, in a circular pit.
Although turntables require a lot of maintenance and are expensive to build and operate, they are very useful in compact areas like in front of a roundhouse.
Wyes
Another very common way to turn a train is to use a “wye” track. This is a triangular track formation, equivalent to doing a three-point turn with an automobile. There is a straight section of track, often part of the mainline track, and two curved sections of track that join to form a “tail track” as shown in the diagram.
The train cars and/or locomotives to be turned leave the main track onto one of the curved tracks. Once they pass the switch at the tail of the wye, the switch there is thrown and the train backs up onto the other curved track and then onto the main line, facing the direction that it came from.
Wye tracks are relatively low cost but they take up a lot of space. There must be enough room for the curved tracks and for a long enough tail track to fit the locomotive and at least a few train cars.
There is often a wye at a junction between two railway lines that meet at right angles. The two right angle tracks form two sides of the triangle and a curved track connecting the two forms the third side.
Loop Tracks
A loop track is basically a large circle of track off the main line. Often it has dual switches so a train can roll right into the loop from the main line, circle around, and return to the main line. Loop tracks are often used to service large industries like grain elevators.
Loop tracks use a lot of real estate but they can hold a large train, and are very convenient for loading or unloading entire unit trains.
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