When a rail vehicle changes tracks, high mechanical forces act on the components of the turnout. Approaching a turnout at an angle is particularly demanding. In this case, the train travels from the start of the turnout toward the switch mechanism. The correct position of the switch blades determines whether the vehicle is safely guided along the intended route.
For rail infrastructure operators, this means that the lock, point mechanism, switch heart, and track superstructure must work together reliably. Precisely manufactured. Mechanically robust. Easy to maintain. In this article, we explain why driving over the point of a switch is critical to safety and what role modern components from Bharat Forge CDP Railsystems play in switch technology.
Why it’s so critical to approach a switch at an angle
A railroad switch allows a train to change from one track to another. It is therefore a key component of the railroad infrastructure. When approaching a switch head-on, the rail vehicle travels toward the tip of the switch. The direction of travel is determined in the area of the switch blades.
In this situation, the moving and stationary components must work together precisely. The switch blade must rest securely against the switch rail. The latch must hold the end position. The wheel set must be guided in a controlled manner. Even minor deviations can affect ride comfort, wear, and operational safety.
The quality of this interface has a direct impact on availability, maintenance requirements, and lifecycle costs in the rail network. Bharat Forge CDP RailSystems develops components and modular solutions for railway technology that are designed for use in demanding switch areas. These include, among other things, switch locks, lock ties, coupling rods, slide plate assemblies, and the EVZ Toolkit for installation and maintenance.
The Evolution of the Railroad Switch: From Manual Construction to Precision Switch Technology
The history of switch technology is closely linked to the dawn of the Industrial Age and the growth of rail networks. The first primitive turnouts were already in use in England in the 18th century to allow for more flexible control of the local mine railroads. However, these early designs were mechanically inadequate and prone to failure, as they often had to be shifted manually and lacked fixed guides.
In 1797, John Kurr described the adjustable switch point, which represented a technological quantum leap for the entire railroad industry. The first switch was thus described in 1797 and laid the foundation for all subsequent developments in modern track superstructure. This innovation made it possible for the first time to continuously switch from one rail track to another without a dangerous interruption in wheel contact.
Over the decades, the demands placed on the railway system have changed dramatically. While low axle loads and low speeds were the norm in the 19th century, modern high-speed lines today require absolute precision. Learn more about the evolution of track systems in this technical article, which provides an introduction to the railway industry and its key disciplines.
Design and Components of a Modern Tongue Divertor
A modern turnout consists of several components that work together precisely. These include, above all, the switch blades, the stock rail, the heart piece, the wheel guide, the lock, and components of the track superstructure. Together, they safely guide the rail vehicle from the main track onto the branch track or straight ahead.
Tongue and Cheek Bar
The switch mechanism is located at the front of the switch. It determines the direction of travel. Depending on the switch’s position, the movable switch blade either rests against the fixed stock rail or is spaced away from it. This determines which path the wheel set takes.
This area is particularly important during the “point-entry” switching maneuver. The train travels directly toward the tip of the switch. Therefore, the adjacent switch blade must be positioned precisely and secured in its final position.
Components such as the switch blade rolling device support the switching process by ensuring controlled movement of the switch blades. It reduces resistance when setting the switch blade and contributes to the reliable operation of the switch.
The Heart and the Wheel Guides
At the rear end of the switch is the switch point, where the rail strands of the main track and the branch track cross. Because a gap in the running edge is created at the tip of the switch point due to its design, the rail vehicle must be guided with precision. This is where double-point crossings or monoblock crossings are used to reduce shock loads.
Across from the heart piece, the wheel guides are positioned on the outer rails. These force the wheel set into the correct track and prevent the wheel rim from accidentally running in the wrong direction toward the tip of the heart piece. A robust center piece for the switch, along with the appropriate wheel guide for the switch, is essential for reliably preventing derailments in this sensitive area.
The key difference: driving into a soft corner with a sharp angle vs. driving into a soft corner with a blunt angle
In rail transportation, a strict distinction is made based on the direction of motion in which a train passes through a set of switches. Both scenarios place completely different stresses on the equipment and require specific monitoring systems.
| Criterion | Take the curve at high speed | Drive over the switch at a low speed |
| Direction of Travel | From the start of the switch to the end of the switch | From the end of the switch to the beginning of the switch |
| Potential Hazards | High (Risk of running in the wrong direction/derailment) | Low (the tongues can be pushed in) |
| Tongue Position | It must be absolutely precise and mechanically locked in place | Depending on the design, it can be moved by the wheel set |
| Force Application | Direct contact between the tongue and the tip of the switch | Continuous integration of the road networks |
Take the curve at high speed
In a “point-entry” switch maneuver, the rail vehicle travels toward the switch point and the switch blades. The position of the switch blades determines whether the train continues straight ahead or is diverted onto the branch line.
That is why the tongue must fit snugly against the side rail. The tip lock and the locking mechanism secure the end position. This prevents the tongue from moving while driving or from hitting the side rail.
Driving Over a Soft, Flat Spot – Procedure and Special Considerations
If, on the other hand, the rail vehicle travels from the end of the switch toward the beginning of the switch, this is referred to as a blunt approach. In this case, the two converging track sections merge into a single track. If the switch is not in the correct position for the approaching rail vehicle, the switch blades are mechanically forced open by the wedge effect of the wheel sets.
This so-called “cutting” is even an intentional design feature in certain types of turnouts used in switching operations; however, when main-line turnouts are locked, it causes severe damage to the turnout drive mechanism. To better understand how such damage occurs in the track superstructure, it is helpful to review the explanations of how the rail network in Germany fundamentally works.
Type and Speed When Passing Through a Switch
The permissible speed through a switch depends on its design, radius, geometry, and the selected direction of travel. When approaching a switch head-on, the rail vehicle travels toward the switch point and the switch mechanism. Therefore, the switch blades, the cheek rail, the switch drive, and the switch point closure must work together precisely.
The higher the speed and the sharper the switch, the more important it is to ensure stable guidance of the wheel set. The tongue must be securely in place. The locking mechanism must hold the end position. As the train proceeds, the switch point, switch point tip, and wheel guides lead the vehicle through the rail crossing.
Depending on the application, different designs are used:
- Simple turnout: connects a main track to a branch track.
- Inner-curve turnout/ Outer-curve turnout: Used in curved track sections.
- Crossing switch: allows for track changes and crossings in confined spaces, such as at a train station.
- Return switch: Can be used on branch lines or passing tracks and returns to a defined position after a train has passed through it.
Safe operation depends not only on the individual switch configuration, but on the entire system. The design, position, movement, and locking mechanism of the switch must all be coordinated. Components and modular solutions from Bharat Forge CDP RailSystems support precisely these requirements in modern switch technology.
Locking Mechanisms and Switch Actuators in Detail
To ensure that a switch can be approached at an acute angle without the switch blade moving under the train, an absolutely reliable locking mechanism is essential. The switch actuator moves the push rod, which in turn pushes the switch blade assembly into the desired end position.
As soon as the end position is reached, the tip lock engages. It ensures that the adjacent tongue remains securely locked to the jaw rail, while the offset tongue provides the necessary clearance for the flange. A failure of this system would have catastrophic consequences for rail traffic.
One particularly proven system is the mechanical switch point lock. Learn more about this in the technical article on the switch point lock in the context of modern switch safety, as well as in the supplementary article on the general switch point lock and its significance. These mechanical safety devices are supplemented by robust switch locks and integrated coupling rods, which ensure the synchronous transmission of the actuating forces.
Fail-back switch and cutting
A return switch is a special type of switch. It can be used, for example, on branch lines or at passing tracks. After a train has passed through it, it returns to a predetermined position.
If a turnout is entered head-on, the wheel sets can mechanically force the switch blades open, depending on the design. This process is called “cutting open.” For certain types of turnouts, this may be intended. However, with locked turnouts, it can cause damage to the turnout drive, the push rod, or the lock.
If a switch that has been previously cut open is subsequently approached at an angle, the correct final position must be clearly secured. Otherwise, misrouting, tongue impact, or—in the worst-case scenario—a derailment could occur.
Risk Management: Setting the Course and Preventing Derailments
The unintended cutting of a switch or an incomplete closure of the switch blades poses significant hazards. If a train attempts to enter a turnout at an acute angle that was previously mistakenly set to a blunt angle, the switch blades will no longer be in the correct position. This inevitably leads to a derailment, as the train’s wheels are directed onto two different tracks (two-track running).
To prevent this, electromechanical monitoring systems and the traditional turnout lock are used. In addition, the load-bearing ties in the turnout area must withstand enormous loads. A modern locking sleeper integrates the locking mechanism directly inside the sleeper, where it is protected, which drastically reduces wear caused by environmental factors and maximizes operational safety.
Components from Bharat Forge CDP Railsystems for Maximum Reliability
Modern rail infrastructure requires advanced materials and intelligent system solutions. To withstand the harsh conditions of high-speed rail traffic, all slabs and joints used must meet extremely tight tolerances. A stable track structure significantly reduces the life-cycle costs (LCC) for rail operators.
High-quality slide chair plates contribute to this by enabling low-friction and precise sliding of the switch blade. The robust Unibar connecting plate also serves to securely fasten the rail sections in the transition area. Learn more about the design principles of modern railways in our specialized articles covering everything you need to know about ribbed plates in track construction and about Vignol rails as the backbone of the infrastructure.
In addition, advanced joining techniques play a key role in the construction of safe railways. Welding rails reduces shock and minimizes wear on the material. Detailed insights into these manufacturing processes are provided in the technical articles on burn-through butt welding in track construction and the overview of general processes and quality standards for rail welding.
Conclusion and Outlook for Sustainable Rail Infrastructure
Safe operation of point switches is a prime example of the perfectly coordinated interplay between sophisticated mechanics, precise signaling technology, and robust materials science. Since point switches form the critical junctions of any rail network, their quality directly determines the reliability of the entire rail transport system. The use of durable forged components made of steel and aluminum minimizes maintenance requirements and maximizes line capacity.
As an innovative partner, Bharat Forge CDP Railsystems supports the global expansion of modern transportation networks with future-proof products. Continuous optimization of components is the key to the success of rail-based transportation. Discover more detailed information about modern rail systems in the technical article on improving rail infrastructure for sustainable transportation solutions.