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Primary Protective Role of Railway Guardrails
Along railway lines, they use a type of guardrail that keeps the train on the tracks if the train has to suddenly change direction or if a car drives over the tracks. If a train was to hit the end of the tracks, the huge guardrails that enclose the tracks and the train wheel flanges when the train tries to derail become a point of force that keeps the train on the critical track. If the guardrails were not there, the train would climb the track, derailing it. Outside forces that push the train side to side cause the train to move back to the track. Primarily, the force on the rails is vertical, the sideways forces that would cause derailments are supported by the guardrails. Containment guardrails at critical points like junctions, bridges, and road level crossings are the difference between losing a derailment and endangering the lives of the people on the train or the people and cargo being transported by the road.
How Lateral Threats at Level Crossings are Mitigated by Railway Guardrails
When cars or trucks drive onto train tracks, train-vehicle collision accidents are highly likely to happen. However, railway guardrails at road-rail crossings reduce the chances of collisions and accidents by absorbing and deflecting the impact of the collisions. To do this, railway guardrails provide impact deflection and control system components to guide and redirect the collision incidents at level crossings. Lateral train derailments can also be prevented by the control and guide functionality of the guardrails. In additions to saving lives and significant community cost, guardrails protect crossing and derailment control systems and railway track equipment. During construction, the location of guardrails is determined to provide optimal protection against vehicle crossings.
Wheel Guidance Under Collision: Redirecting Off-Track Motion
During a side collision, a barrier can achieve a few functions:
Flange Containment: They trap wheel flanges, preventing lateral drift.
Impact Force Redirection: Oblique-impact surfaces shift lateral momentum to longitudinal motion along the rail.
Wheel Climb Prevention: Their specific heights prevent wheel climbing over the rail.
This system of integrated confinement can maintain wheel-track alignment, even with severe lateral force applications. The FRA data indicates that crossings with guards experience 74 percent more derailments than those without guards. This illustrates how the design of rail barriers mitigates derailments to a limited event.
Purposeful Design of Railway Guardrail on Risky Infrastructure
Railway guardrails are designed only where the risk of derailment is high, never on the random principle, and therefore, on curved sections of tracks, the guardrail is prioritised. This is because centrifugal force pushes a rolling stock outward, increasing the contact pressure between the flange and decreasing the adhesion. In a high lateral thrust scenario, the risk of derailment increases significantly.
Physics-Informed Positioning: Managing Centrifugal Force and Flange Contact
The construction of the inner rail on curves contains guardrails. The spacing of the rails is close and is usually 6 to 12 inches from the running rail and is designed about the rail line class and speed, and geometry of the rolling stock, including. This close spacing helps to do the following:
Intercept wheel flanges before derailment happens
Minimize the lateral displacement to reduce flange climbing
Gently recenter the wheel back to the running rail
The guardrail is designed at a certain stiffness and angle to stabilize and absorb the kinetic energy during contact with the guardrail, and to avoid the contact guardrail from causing a sudden deceleration, or from structural failure. The same risk-based reasoning is applied to the placement of guardrails on bridges, tunnels, and embankments because of the increased risk to the guardrail and the surrounding area, thus establishing a comprehensive, risk-based safety area.
Railway Guardrail vs. Check Rail: Partnering for Safety
In ensuring safety on the railway, guardrails and check rails perform different functions. Guardrails are installed on the inside edge of railways on bridges and level crossings, which are the most accident prone areas. Their primary purpose is to contain a derailment. When a train wheel comes off the rail, the guardrail will guide and deflect the wheel away from the outside area of the rail, absorbing some of the impact. Check rails perform the opposite role. Check rails are installed on the inside edge of a rail on a curve. Check rails actively manage the effect of centrifugal force by “grabbing” the flanges of the wheels, which keeps the wheels inside the rails, and aligned appropriately, during a turn. This works is in contrast to check rails, which in some locations, are expected to perform their function without being noticeable. Guardrails are used in areas where the consequences of failure would be most severe. In contrast, the presence of check rails is most prevalent in locations where the railways require routine maintenance.
Feature Railway Guardrail Check Rail
Primary Purpose Redirect derailed wheels Prevent wheel climbing on curves
Trigger Post-derailment containment Pre-derailment prevention
Key Installation Bridges, level crossings Sharp curves (>2° cant deficiency)
Mechanical Action Absorbs lateral impact energy Constrains flange gap dynamically
Frequently Asked Questions
What is the primary function of railway guardrails?
Railway guardrails primary function is to redirect lateral forces that are involved with derailments or collisions during critical infrastructure events at curves, switches, and level crossings.
Where are railway guardrails mostly installed?
Railway guardrails are installed at high-risk locations for derailment like sharp curves, bridges, tunnels, and level crossings that are subject to external forces like the centrifugal force or vehicle incursions.
How do railway guardrails differ from check rails?
Rail guard fences are designed to manage derailment by redirecting wheels and managing lateral impact energy. Check rails, on the other hand, are designed to keep wheels in alignment and positioned during tight curves.