FACT SHEET: Broken Rails
Winter in New England brings a range of inclement weather, including snow, ice, freezing rain and extreme cold, all of which can impact train operations and the railway infrastructure that supports the system. These conditions can sometimes lead to cracks or vulnerability in the rails. Below is information regarding the causes and conditions around broken rails, and what Keolis is doing to prevent any resulting delays while also maintaining the highest standards of safety and security for our passengers.
What can cause broken rails?
- The steel rails that support railway track are strong and durable, built to carry hundreds of millions of tons of traffic over their lifetime. Our system’s rails can last decades depending on the kind of traffic and whether it is a curved track.
- Small defects in rails may be present, from either manufacturing, installation, or they may develop over time as trains pass over. These small defects, can grow over time and, in rare circumstances, cause the rail to break. In order to detect them before reaching a critical size, we use high tech technologies such as ultrasonic testing of rails with specialized trains running among revenue service. But even with such advanced technology some defects are difficult to find.
- Most broken rails occur in winter. In very cold conditions, rails can be five degrees below the air temperature, creating additional tension in the steel. Under these conditions small defects in rails are more prone to breaking, particularly when a train passes over them.
Secondary impact of broken rails:
- A rail network is divided into small sections of track which form separate electric circuits. These circuits provide a vital function, allowing signal systems to “see” where trains are and ensure that they remain a safe distance apart.
- When a rail breaks, the electrical circuit is broken – known as a track circuit failure – and we must stop trains until the problem is solved. These track circuit failures enable us to detect broken rails and respond quickly.
How we are addressing small rail defects, preventing related delays and maintaining train safety:
- Keolis’ on-track teams regularly check rails for damage and remove small surface defects to prevent grinding against the head of the rails. Using a “Measurement Train” equipped with ultrasonic and high definition video equipment, we can intervene before any defects grow to a size that may result in a broken rail.
- The more heavily a line is used, the more frequently we check it for defects. Keolis runs checks twice a year.
- When a defect is found, immediate speed restrictions are imposed to ensure safety without disrupting service. Full repairs are then organized during the next two-hour gap between trains. Otherwise, repaired will be deferred to the evening to not cause any disruptions.
- Where possible, we replace bolted joints between rails with welded joints which are stronger and less likely to break.
- If a rail breaks, it may be possible to clamp it and allow trains to continue running, subject to speed restrictions, until the rail is replaced.
- Keolis works with rolling stock manufacturers to minimize the damage caused by trains- striking the right balance between shape of wheels and rails or hardness and suspension.