Ensuring Safety: How High-Speed Trains Stay on the Tracks

Trains, like any other locomotives, must adhere to strict safety protocols to ensure secure travel along their designated tracks. This article delves into how high-speed trains maintain stability during operation and what measures are in place to prevent derailments. From the physics principles governing their motion to the engineering features that keep them safely aligned, this guide provides an in-depth look at the mechanisms at play.

The Fundamentals

The principle underlying the safety of high-speed trains is rooted in the laws of physics. Isaac Newton’s Second Law states that an object in motion will stay in motion unless acted upon by an external force. Therefore, the forces that cause trains to deviate from their tracks are carefully managed to ensure a smooth journey.

Self-Correcting Wheels

To keep a train centered, its wheels are designed with a slight cone shape. If the train strays too far to one side, the larger diameter of the wheel on the opposite side forces it back into the center. This inherent mechanism is similar to the dihedral angle on an airplane wing, which helps keep the plane stable during turns.

Flanges and Irregularities

For more extreme deviations, the wheels are designed with flanges. These flanges maintain contact with the track edges, providing additional stability. If a flange encounters an irregularity or a poorly joined section of track, it can snag and provide a sudden upward force. This force is usually not enough to lift the entire train, but it can be sufficient to disengage the flange from the rail, leading to a derailment if further aggravated by the train's mass.

Curved Tracks and Superelevation

When navigating curves, the track is constructed with a “superelevation” or bank, which helps balance the train’s lateral force with the necessary centripetal force required to keep it on the track. This banking is designed to ensure that a train traveling at the prescribed speed experiences a neutral lateral force, making derailments less likely.

Recent Derailment Incidents

A partial derailment can occur due to a combination of factors. For instance, a photo taken on September 25, 2022, shows the check rail on the Monbulk bridge, a necessary component that helps prevent the train from deviating. Similarly, images of the landslide area from 1954 and the Sydney Harbour Bridge in 2022 highlight situations where track irregularities can lead to derailments. In all cases, the presence of these irregularities can disrupt the train's normal path and, in some instances, lead to a full derailment.

Speed Limits and Prevention

While the geometric design of tracks helps prevent derailments, safety also relies on strict speed limits. Trains, even at high speeds, can maintain their track when following these guidelines. Occasionally, a train may go off the tracks if the speed limit is exceeded, leading to a momentary disruption in the journey.

By understanding these principles and the engineering features in place, we can better appreciate the complex yet effective mechanisms that ensure high-speed trains stay safely on the tracks. Preventing derailments not only ensures passenger and cargo safety but also maintains the integrity and efficiency of rail transport systems worldwide.