All aboard!
Have you ever wondered how locomotives are turned around on the tracks? The answer lies in a fascinating piece of railroad technology known as the turntable.
While most of us associate turntables with spinning vinyl records, these rotating platforms have been a crucial part of rail transportation for over a century.
In this article, we’ll explore the history and mechanics of railroad turntables, and discover how they continue to play an important role in modern rail operations.
So grab your conductor’s hat and let’s get started!
What Is A Railroad Turntable
A railroad turntable is a device used to turn railway rolling stock, such as locomotives, so that they can be moved back in the direction from which they came. The earliest use for a turntable was to redirect trains. The very first locomotives could only run in one direction, so a device was needed to turn them. Even with bi-directional trains today, turntables are still used as a convenient means for moving locomotives and other equipment onto tracks headed in the correct direction.
Turntables are electrically operated from a control booth that is installed on the turntable. Employees controlling it from the booth ride and rotate with the equipment being turned. Although there are other rail structures that can be used to achieve such turning, like the wye and balloon track, turntables are unique in that they require the least amount of space to do so. This was part of the appeal of turntables back then; they took up less ground, making the design more practical to build than their locomotive-turning counterparts.
Interestingly, railroads in North America tended to have fewer turntables and more wyes than railroads elsewhere. Many believe this was a direct correlation to the continent having greater available land capacity than others at the time of construction. However, as Northern American railroad networks grew, so did consideration for turntables.
The History Of Railroad Turntables
The history of railroad turntables dates back to the 1830s, many years before the phonograph was invented in 1877. At that time, the very first locomotives could only run in one direction, so a device was needed to turn them around for return trips. This is where the turntable came into play.
Turntables were especially used in areas where economic considerations or a lack of sufficient space made it difficult to construct a turnaround wye. They were also used to turn observation cars so that their windowed lounge ends faced toward the rear of the train.
In the case of steam locomotives, railways 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. In the case of diesel locomotives, though most can be operated in either direction, they are treated as having “front ends” and “rear ends” (often determined by reference to the location of the crew cab).
When a diesel locomotive is operated as a single unit, the railway company often prefers or requires that it be run “front end” first. When operated as part of a multiple unit locomotive consist, the locomotives can be arranged so that the consist can be operated “front end first” no matter which direction the consist is pointed.
Turntables were also used to turn observation cars so that their windowed lounge ends faced toward the rear of the train. Roundhouses were served by turntables which were used to line up steam locomotives with their berths in the roundhouses. On rural branch lines, turntables sometimes existed without an associated roundhouse or engine house.
Today, turntables are still used as a convenient means for moving locomotives and other equipment onto tracks headed in the correct direction. They are electrically operated from a control booth that is installed on the turntable and employees controlling it from the booth ride and rotate with the equipment being turned.
How Railroad Turntables Work
Railroad turntables work by using a circular platform, typically made of steel, that rotates around a central pivot point. The platform is supported by a bridge with rails, which can accommodate the railway vehicles. The turntable is driven by an electric motor, which moves along a rail that runs parallel to the circular turntable pit. The motor and the wheels running along the rails create the sounds of the railway turntable.
When a locomotive needs to be turned around, it is driven onto the turntable and positioned in the center. The operator in the control booth then activates the motor, and the turntable begins to rotate. As it rotates, the locomotive moves with it until it is facing in the desired direction.
Turntables were particularly useful for steam locomotives with a trailing tender, as they could only attain maximum speed when moving forwards and could not pull a train in either direction. Therefore, turntables were predominantly situated at main train stations and in train depots, right by the roundhouse. The roundhouse enabled easy access to the individual locomotives’ maintenance areas, which would otherwise only be possible by a complex network of switches.
Today, turntables are still used in yards to maintain and employ Positive Train Control (PTC) – a system that monitors the position and speed of trains to prevent collisions and derailments. PTC is placed on the lead locomotive of a train, therefore not every locomotive is equipped with PTC. If an available locomotive in the yard with PTC is facing the opposite direction, it can be navigated by operations personnel to a turntable, which would rotate it in the desired position and then place it at the front of the train.
Types Of Railroad Turntables
There are two main types of railroad turntables: locomotive turntables and railcar turntables.
Locomotive turntables are custom designed and manufactured to meet specific capacity and length requirements. They have two drive systems, one at each end of the turntable bridge, each of which utilizes variable speed motors for smooth start and stop functions, as well as quiet operation. Automatic wheel chocks and rotation locking devices are available, as well as an open weather-proof control station or an enclosed operator control area. Locomotive turntables are primarily used for turning locomotives around for return trips, especially in areas where economic considerations or a lack of sufficient space have served to weigh against the construction of a turnaround wye.
Railcar turntables, on the other hand, are engineered with precise tolerances that allow the variable speed drive system to rotate the vehicle efficiently. The result is a turntable that combines high volume with lower power consumption and less maintenance and downtime. Railcar turntables can be used to turn railcars around for return trips or to redirect them onto tracks headed in the correct direction. The top of the turntable can also be built to contain both rails and a road surface, so that non-rail vehicles (such as rescue vehicles) can be driven across the turntable.
Modern Uses Of Railroad Turntables
While turntables were originally used to redirect trains and turn locomotives around, they have evolved to serve many modern purposes in railroad operations. For example, turntables are now used in yards to maintain and employ Positive Train Control (PTC) – a system that monitors the position and speed of trains to prevent collisions and derailments.
PTC is placed on the lead locomotive of a train, which means not every locomotive is equipped with PTC. If an available locomotive in the yard with PTC is facing the opposite direction, turntables are extremely useful in turning this dilemma around. Operations personnel can navigate the PTC-equipped locomotive to a turntable, which would rotate it in the desired position and then place it at the front of the train.
In addition to PTC, turntables are also used for maintenance and repairs. Several vintage turntables associated with roundhouses still remain in service today. Roundhouses were mechanical shops where maintenance and repairs were conducted. The semi-circular buildings were constructed around the turntable, which sat in the center as the focal point. Many tracks would dead-end into the roundhouse and meet at the turntable. As locomotives moved onto the turntable, they’d be rotated and moved onto the tracks leading into one of the stalls to be serviced by mechanics. The process would be repeated in reverse to put the locomotive back in circulation once repaired.
Challenges And Limitations Of Railroad Turntables
While railroad turntables have been a valuable tool for the railroad industry, they do come with some challenges and limitations. One of the main limitations is the size of the turntable. Turntables can only accommodate a certain length of rolling stock, which can be a problem for longer locomotives or trains. This means that some rail yards may need to have multiple turntables to accommodate different sizes of rolling stock.
Another challenge is the maintenance and upkeep of turntables. As with any mechanical device, turntables require regular maintenance to ensure they are functioning properly. This includes lubrication of moving parts, inspection of electrical components, and replacement of worn parts. The cost of maintenance and repairs can be significant, especially for older turntables that may require specialized parts or expertise.
Turntables also require a certain amount of space to operate, which can be a challenge in urban areas where space is limited. In some cases, rail yards may need to be located outside of city limits to accommodate the space needed for turntables and other rail infrastructure.
Finally, turntables can be slow and time-consuming to operate. It can take several minutes to rotate a locomotive or other rolling stock, which can cause delays in rail operations. This is especially true if multiple pieces of rolling stock need to be turned around.
Despite these challenges and limitations, turntables remain an important tool for the railroad industry. They provide a convenient and efficient way to turn locomotives and other rolling stock, allowing trains to continue on their journey without the need for additional tracks or infrastructure. As technology continues to advance, it will be interesting to see how the railroad industry adapts and evolves its use of turntables in the years to come.
Preservation And Restoration Of Railroad Turntables
Preserving and restoring railroad turntables is crucial in maintaining historical landmarks and ensuring that they continue to function for future generations to enjoy. Many turntables are associated with roundhouses, which were mechanical shops where maintenance and repairs were conducted. Roundhouses look exactly as they sound. The semi-circular buildings were constructed around the turntable, which sat in the center as the focal point. Many tracks would dead-end into the roundhouse and meet at the turntable. As locomotives moved onto the turntable, they’d be rotated and moved onto the tracks leading into one of the stalls to be serviced by mechanics. The process would be repeated in reverse to put the locomotive back in circulation once repaired.
Several organizations have taken on the task of preserving and restoring turntables across the country. The Colorado Railroad Museum has a four-rail turntable as part of the Cornelius Restoration Roundhouse, while the South Park Historical Society has restored a turntable and the stone Roundhouse at their site in Como. The Nevada County Railroad Museum at Nevada City, California, even has a small hand-powered turntable.
Restoring these turntables requires a significant amount of effort and resources. Many of these structures have been neglected for years, suffering from rust, decay, and vandalism. Restoration work often involves disassembling the turntable, repairing or replacing damaged parts, and repainting it to its original color scheme. In some cases, entire roundhouses have been reconstructed to accompany the restored turntable.
Preserving these historical landmarks is not only important for their cultural significance but also for their practical use in modern rail operations. Turntables are still used in yards to maintain and employ Positive Train Control (PTC) – a system that monitors the position and speed of trains to prevent collisions and derailments. A PTC equipped locomotive must be placed on the lead of every train operating on PTC territory. In the instance that a locomotive is not equipped but is placed in the lead position, it would need to be replaced with one that is. Turntables are extremely useful in turning this dilemma around by rotating the locomotive into position.
In conclusion, preserving and restoring railroad turntables is crucial in maintaining historical landmarks and ensuring that they continue to function for future generations to enjoy. These structures have played a significant role in rail operations throughout history, and their practical use continues today.
