Enhanced Braking System Installed on Trains to Combat Leaf-Related Slippage

A novel system designed to enhance train braking performance amidst slippery conditions caused by autumn leaf fall has been installed on the specific train model implicated in two significant accidents. This mechanism dispenses as much as 5 kilograms of sand per minute onto the tracks, directly ahead of the wheels, thereby enhancing traction. Testing indicates that it can halt a train on slick rails in half the distance required by previous apparatus. The system has been implemented across a fleet of 39 trains stationed at the Salisbury depot. These trains operate on the west of England route connecting London Waterloo and Exeter, as well as on routes passing through Romsey. Comparable Class 158 / 159 diesel trains were implicated in a deadly collision at Talerddig, Wales, last month, and in another collision at the approach to Salisbury tunnel in 2021. In both occurrences, the trains proceeded past signals indicating danger, entering the path of another service. Insufficient adhesion in regions characterized by substantial leaf fall constituted a significant contributing element in each accident. When foliage is compressed into a slender, dark film, the railhead’s surface acquires a slipperiness comparable to ice. The area of contact between a train wheel and the rail is approximately the size of a five pence coin. Consequently, even with full braking applied, a train may slide along the rail, incapable of maintaining traction. This novel apparatus, developed by Siemens and financed by Network Rail, has been installed on the three-decade-old South Western Railway trains. Neil Drury, engineering director at SWR, clarified, “It increases the friction level between the wheel and rail.” He added, “The greater the friction, the better the braking.” These particular trains were not initially equipped with any sanding mechanisms. The initial iteration was a single-application device, activated by the driver solely in emergencies. “Next was a standard-rate sander. Now we have a variable-rate system, releasing sand in relation to train speed and track conditions.” Evaluations conducted by the Rail Safety and Standards Board demonstrate that this system can bring a train to a halt on slippery, wet rails in half the distance of earlier equipment, one-quarter the distance of a train without any sanding capability, and double the distance of a comparable train braking under optimal dry rail conditions. Regarding whether the new apparatus could have averted the collisions at Salisbury tunnel and Talerddig, Mr. Drury commented, “It’s a good question, but we can’t tell.” He further elaborated, “The top of the rail surface at Salisbury was particularly contaminated. What we can say is that the sand system is an incremental step more effective than was fitted previously.” This new equipment complements the existing specialist railhead treatment trains, which Network Rail deploys daily from October to December annually to remove leaf mulch. These trains apply a gel to the track. These various approaches address the symptoms of slippery rails rather than their root cause. Proactively reducing lineside vegetation would eliminate the issue fundamentally. Rob Breckon, a spokesperson for Network Rail, stated: “We do a lot of things to tackle leaf fall, particularly on this route. It includes chopping down trees, as part of our programme of vegetation management. “But we have to do that in a responsible way, and it is not possible to cut down every tree that lines the railway.” For updates, follow BBC Hampshire & Isle of Wight on Facebook, X (Twitter), or Instagram. Copyright 2024 BBC. All rights reserved. The BBC bears no responsibility for the content of external websites. Information regarding our approach to external linking is available.