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How slip-slide affects your commute and how we're combating it

In autumns past, you may have heard our train crews mention "slip-slide" to explain minor service delays.

Updated October 28, 2022 3:47 p.m.

Slip-slide is a condition created by a slimy substance left by crushed leaves on our rails that gets even more slippery after it rains. When a train attempts to speed up or slow down, this substance can cause the wheels to slip or slide along the rails. In severe cases the train will automatically make an emergency stop, because the on-board computer system perceives "slip-sliding" as the train not slowing down when it should. Slip-sliding during braking also creates flat spots on the train's wheels, forcing us to take much-needed equipment out of service for repairs.

Over the past several years, the railroads have taken a proactive approach to combating this problem.

Metro-North Railroad has taken the following actions: 

  • Instructing our engineers to report slippery conditions immediately to our Operations Control Center. (We have also provided additional training in how to operate through these "slippery" areas.)
  • Enhancing our computerized train-tracking system to allow for automatic reporting of slip-slide incidents and conditions, enabling us to take corrective action more quickly.
  • Installing a Wheel Impact Load Detector (WILD) across all four tracks in the Park Avenue Tunnel. This monitors for wheel flats that may have developed during operation and allows us to identify and prioritize wheels for repair.
  • Installed a tandem Wheel Truing Lathe in Harmon Shop. We built a state-of-the-art wheel true facility in Harmon that can cut both wheels on a truck simultaneously. This allows for proper wheel diameter matching and also helps us return cars to service more quickly so we have enough cars available for our customers. The Connecticut Department of Transportation has built a second identical facility in New Haven to support our M8 Fleet. 

Metro-North also stepped up efforts to keep its right of way as leaf-free as possible. This is no small feat given the number of trees that line our tracks. Metro-North uses two large high-pressure rail washers and several smaller rail scrubbers to remove crushed leaf residue from the tracks. On-board "sanders" on our diesel trains automatically drop sand on our tracks to help improve traction and reduce wheel slippage when it begins to occur.

The Long Island Rail Road’s efforts to fight slip-slide conditions include:

  • Industry-leading laser trains on tracks to vaporize the slippery substance
  • Utilize high-pressure (20,000psi) water trains to ‘power wash’ the  substance from the rails
  • Monitor real-time conditions and implement solutions as slip-slide events occur
  • Operator training for better rail low adhesion awareness and mitigating actions
  • Vegetation management to reduce the source of the problem

You may notice that under extreme slip-slide conditions, we reduce speeds through problem areas. While this may result in a slight delay, it ensures the safe operation of our trains and prevents a greater delay because of wheel damage. No flat spots on train wheels also means we can operate at regular speeds in non-problem areas, and we don't need to take the equipment out of service to repair it.

Please keep in mind that while we can reduce the incidents of slippery rail, we cannot eliminate them. We will continue our efforts to try to minimize any delays and inconvenience slippery rail may create for you this autumn. And, as always, we appreciate your patience.