How Transit Works in Snow and Ice

Dec 21, 2018

We’ve enjoyed a mild fall, with less precipitation than normal and plenty of sunshine. That means we can expect a mellow winter, right? We’re certainly not counting on it.

Over the years, we’ve learned that winter storms can appear out of nowhere. Of course, we monitor forecasts and share information with partners like PBOT and the National Weather Service to help us prepare for snow and ice. But weather isn’t always straightforward — and no two storms are the same — so we’re always at the ready with a plan.

Making the Call

We value safety, so determining whether to alter service in a winter weather event is simple:

If a situation is potentially unsafe for riders, operators or equipment, we take action.

In practice, this means being ultra-aware of conditions across the system. To make this easier, we set up an Emergency Operations Center (EOC) that’s staffed around the clock during severe winter weather events. Representatives from every division of the agency convene to track conditions and respond accordingly. This nimble structure streamlines and speeds up the process of gathering information, making decisions and disseminating information. (Activating an EOC during an emergency is standard practice across all types of agencies.)

The Plan for Buses

Preparing buses for snow and ice often begins before service starts for the day. Specialized crews known as “Snowbirds” head out to assess bus routes, particularly those at high elevations, to see if they’re safe for normal bus operations. They might call for a sanding truck, reroute the line or cancel a run entirely.

Like other cars and trucks on the road, buses will often be chained if they’re running on snowy or icy streets. It takes a little under two minutes to install chains on each tire, and up to ten hours to chain all our buses. Depending on the forecast, we may chain just part of our fleet — if the weather suddenly improves, we need to be able to remove the chains quickly.

And if it gets really cold, buses will idle overnight to keep their engines warm and to prevent air systems from freezing. (Essential components like brakes, doors, wipers and starters are all air-operated.)

For riders, it’s important to keep in mind that chained buses travel slower — no faster than 25 mph — so they won’t stay on schedule. And in winter conditions your bus won’t pull up to the curb, lest it slide or become stuck. If that happens, we have rescue teams on standby to get it moving again.

MAX Service

MAX typically does well in snow, and we take measures to prevent ice buildup. Throughout the system, switches on the track are equipped with covers (some have heaters, too) and portions of the overhead wire have caps to keep ice at bay.

Some of our Type 1 MAX cars (the model with the stairs) have a special pantograph (the arm that connects the train to the overhead wire) equipped with an ice cutter that can shave about a millimeter of ice off the overhead wire with each pass. It doesn’t sound like much, but every little bit helps.

Recently, we installed a heating system on the overhead wires in the Ruby Junction rail yard as part of a pilot project to prevent ice buildup. If it works, we’ll consider using the technology throughout the system.

If necessary, we’ll run some trains overnight to keep ice from building up on the overhead wire. And if you’re at the station when one of these trains pulls up — for whatever reason, at whatever time — we’ll let you board!


We have a supply of ice melt on hand to keep walkways, platforms, stairs and transit centers walkable. (We use magnesium chloride, an environmentally friendly and biodegradable liquid.) If you find that your stop or station is dangerously slick, let us know. We’ll try to get someone there to help as quickly as possible.

This is common sense, but it’s worth repeating: If it’s snowing or icy, be very careful when you’re making your way to your stop or station. Even if a path looks clear, it can be slippery.

What You Need to Know

We often need to alter service in the face of unpredictable weather, so start by checking for updates on your lines: You’ll find service alerts and detours at and on Twitter, or you can subscribe to email updates for the lines you ride. And if you have questions or comments, we’re available 24/7 to help.

We’ve already mentioned that your bus will likely be running late and a little slow — and perhaps on a detour — during snow and ice. If it gets too far off its normal schedule, we’ll turn off TransitTracker so estimated arrival times (which aren’t accurate when buses are traveling slower) become approximate distances.

When you’re ready to catch the bus, keep in mind that it it can’t safely stop on a slope — so if your stop is on a hill, head to the top or bottom to board. And wait on the sidewalk until the bus comes to a complete stop before trying to board. There’s always a chance it could slide toward the curb once the brakes have locked the wheels.

Aside from checking the status of your bus or train before starting your trip, make sure your phone is charged and that you have water and warm clothing — don’t forget gloves and a hat. Leave plenty of time to walk to your stop or station and be extra careful on slopes. Along with our regional partners, we do our best to de-ice roads, bridges, garages, platforms and parking lots, but you’ll likely find some slippery spots along the way.

As we mentioned at the top, our goal is to keep everyone safe. So even as things slow down, know that there’s a lot going on behind the scenes to coordinate safe travel in difficult circumstances. Winter weather requires extra effort from all of us, and we appreciate your trust, patience and preparedness when the time comes.


Brian Lum

Brian Lum

Web & Social Media Coordinator

I'm here to help tell our story, and to share the interesting things I find along the way. When I'm not here, you'll find me out riding my bike and taking pictures. | All posts

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