Why bad weather can delay your train

Some of you have pondered why certain weather conditions like fog, rain or snow can cause major delays to your train ride. We briefly touched upon this in our February/March 2011 issue of Metrolink Matters but wanted to give you a more in-depth explanation of how weather can affect train operations.

Adverse weather conditions can stop a train dead in its tracks, literally. To keep you safe, our operations team decides whether train operations should be slowed or temporarily suspended; if we suspend train service we provide alternative modes of transportation to you.

We thought it might be helpful to first give you a little background on railroad equipment and the signal system our engineers follow.

As you know, when engineers operate trains they have to heed “traffic” signals, just like people do every day when they drive cars. Whenever there is a problem with rail equipment, including the track and circuits, the signals default to red for safety reasons. That prompts the engineer to stop the train, which prevents an accident from occurring or further damaging equipment. Metrolink deploys staff on the scene as soon as possible to make repairs or adjustments, according to Jaime Romo, Metrolink’s signal manager.

I love that we still have “beach days” in the middle of winter here in Southern California, but we sometimes have “nasty” weather that can affect the railroad: cold, heat, fog, strong winds and rain. Because rail is made of steel, it expands or contracts depending on the temperature.

Rail expands and can break in cold temperatures, which can cause delays. But, as I mentioned earlier, the way our signal system works is that signals default to red when a problem surfaces.

When heavy fog and snow impairs an engineer’s ability to see a signal, he must treat the signal as red. Snow also presents a problem to dispatchers, who use switches to move trains from one track to another. When snow falls between the rails and the switches, dispatchers are unable to line the trains up to take different tracks. Metrolink then quickly deploys staff to assist with the switches.

Extreme heat has the opposite effect on rail, causing it to expand and become misaligned. And if a train travels at full speed on misaligned track, problems could occur. That is why we enforce heat restrictions when temperatures surge beyond a certain point, and engineers are then required to operate our trains at reduced speeds.

Like cold weather, heat can also cause problems with the switches. Sometimes the components tighten up, and we have to adjust them.

Strong winds that blow dust onto signals force engineers to slow or stop trains. Strong winds can also break gates at at-grade crossings. When that happens, Metrolink issues a protect order at the crossing to prevent engineers from operating trains at full speed through that crossing.

When heavy rains pour and water rises in excess of 3 inches above the rail, Metrolink has to suspend train operations over the affected track. The same goes when there is a washout. The reason is because water has the ability to affect circuits along the track or the stability of the track. Circuits detect activity on the track, whether it is a train or broken rail, and the signals are determined based on what the circuits detect. When there are circuit problems, the signals and crossings kick into manual mode. This means that trains have to be flagged through crossings at reduced speeds for safety reasons. Heavy rains can also cause mudslides, which make an area impassable until the mud is cleared.

Single track areas, which are track routes where one track is shared by traffic traveling in both directions, are especially affected by weather-related delays. If one train stops no other train can pass through.

But we monitor the weather constantly and prepare ahead of time for potential weather-related challenges. We have workers in place to address problems and get trains back on track as soon as possible, said Romo.

So the next time you see a little drizzle or snow outside and your train happens to be delayed, just remember that getting you to your destination on time is just as important to us as it is to you. But we won’t risk your safety.