Have you ever wondered how locomotives are turned around on the tracks? The answer lies in a fascinating piece of railway technology: the turntable.
Used since the 1830s, turntables were essential for redirecting trains and turning locomotives in the desired direction. They were particularly useful for steam locomotives, which could only run in one direction and had controls that were not configured for extended periods of running in reverse.
But how exactly does a railway turntable work? In this article, we’ll take a closer look at this unique piece of machinery and explore its history, mechanics, and modern-day applications.
So, hop aboard and let’s get started!
How Does A Railway Turntable Work
A railway 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. It consists of a circular pit with a bridge and rails that can accommodate the vehicles. The turntable is driven by an electric motor, although it can also be powered through an air engine or by a hand crank.
The locomotive or other rolling stock is driven onto the turntable and positioned in the center. The turntable is then rotated until the vehicle is facing in the desired direction. The sounds of the railway turntable are made by the motor and the wheels running along the rails.
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.
In modern times, turntables are still used for locomotives and other equipment to be moved onto tracks headed in the correct direction. They 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.
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.
History Of Railway Turntables
The use of railway turntables dates back to the early 1830s, when locomotives could only run in one direction. In the case of steam locomotives, railways needed a way to turn them around for return trips as their controls were often not configured for extended periods of running in reverse. Turntables were an efficient solution to this problem, as they allowed for easy and quick turning of locomotives.
As railroads expanded, turntables became a common sight in most terminals and depots. The turntable was an important device found in most train stations to quickly and efficiently turn locomotives. However, with the advent of diesel technology, the need for turntables decreased significantly. Diesel locomotives could be operated in either direction, making the use of turntables less necessary.
Despite this, turntables remain in use today for various purposes. They are 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. Additionally, turntables are still used for moving locomotives and other equipment onto tracks headed in the correct direction.
Mechanics Of A Railway Turntable
The mechanics of a railway turntable are relatively simple. The turntable consists of a circular pit with a bridge and rails that can accommodate the vehicles. The bridge is rotated by an electric motor, air engine or hand crank. The locomotive or other rolling stock is driven onto the turntable and positioned in the center. The turntable is then rotated until the vehicle is facing in the desired direction.
The turntable’s operation is controlled from a control booth that is installed on the turntable. Employees controlling it from the booth ride and rotate with the equipment being turned. The sounds of the railway turntable are made by the motor and the wheels running along the rails.
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.
In modern times, turntables are still used for locomotives and other equipment to be moved onto tracks headed in the correct direction. 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.
Types Of Railway Turntables
There are several types of railway turntables available, each designed to meet specific capacity and length requirements.
1. Locomotive Turntables: These are custom-designed turntables that can accommodate locomotives of varying sizes and weights. Macton is a company that typically custom designs and manufactures each of these turntables to meet specific capacity and length requirements. The turntable has 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.
2. Railcar Turntables: The same quality and precision that have made Macton locomotive turntables legendary are applicable for rail car turntables. The Macton railcar turntable is 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.
3. Portable Turntables: These are smaller turntables that can be transported to different locations as needed. They are typically used in construction sites or other temporary locations where a permanent turntable is not needed.
4. Combination Turntables: 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. This type of turntable is useful in emergency situations where quick access is needed.
Modern-Day Applications Of Railway Turntables
While turntables were originally used to redirect trains and turn locomotives around for return trips, modern-day applications have expanded to include Positive Train Control (PTC). PTC is a system that monitors the position and speed of trains to prevent collisions and derailments. It is placed on the lead locomotive of a train, therefore not every locomotive is equipped with PTC. 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.
However, turntables are extremely useful in turning this dilemma around. The PTC equipped locomotive would 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. This ensures that all locomotives operating on PTC territory are equipped with the necessary technology to ensure safe travels.
Additionally, turntables are still used in yards for maintenance purposes. They allow for easy access to individual locomotives’ maintenance areas, which would otherwise only be possible by a complex network of switches. This makes maintenance and repairs more efficient and timely.
Maintenance And Safety Of Railway Turntables
Maintenance of railway turntables is crucial to ensure their safe and efficient operation. Regular inspections are necessary to identify any signs of wear and tear, such as cracks or deformations in the bridge or rails. Any defects should be addressed immediately to prevent accidents and ensure the longevity of the turntable.
Lubrication of the moving parts is also important to prevent rust and ensure smooth operation. The electric motor, gears, and bearings should be inspected and lubricated regularly to prevent friction and reduce wear.
Safety measures must also be implemented when operating a railway turntable. Employees working on or around the turntable should be trained on proper safety procedures and wear personal protective equipment, such as hard hats and safety glasses. The control booth should be equipped with emergency stop buttons in case of a malfunction or accident.
Regular maintenance and safety checks are necessary to ensure the safe and efficient operation of railway turntables. By implementing these measures, railroads can continue to rely on turntables as a convenient means for moving locomotives and other equipment onto tracks headed in the correct direction.
