Who knew trains could get flat tires?

The first day on the job is always an exciting one. For me, my first day at Valley Metro included a tour of the garage in the light rail Maintenance of Equipment building. It's a cavernous space where trains get some TLC. That could include work on air conditioners, removal of wheel assemblies (also known as "trucks"), and the application of advertising decals.

For a first timer like me, I got a real kick being behind the scenes to see a crew of skilled technicians working to maintain these massive vehicles. During my tour with Rail Operations Assistant Manager Debby Thacker, we came across a large bin filled with what looked to be springs.


Thacker explained that those weren't springs, they're what's left over when a train's wheels are shaved.

The wheels get a shave?

Yes, she explained, it's a process called "trueing."

The fact is, train wheels can get flat spots. Light Rail Vehicle Maintenance Assistant Superintendent Brian Probasco says sometimes it happens when a train's emergency brakes are applied. The wheels lock up, and all that weight puts some serious stress on wheels, leaving a flat spot. It can also occur in the event of an mechanical failure.


When flat spots happen, there's a steady rhythmic "clack" that's easily heard and felt throughout the train. Sometimes the train operator is the first to notice since the operator cabs tend to be a lot quieter than the rest of the vehicle.

Flat spots lead to an unsteady ride and Valley Metro takes the issue very seriously. Trains with flat spots are quickly taken to the Maintenance of Equipment building for a tune-up. If possible, the entire train will be positioned over a trueing machine that literally shaves off the flat spots on the wheel.


The train's wheels are spun rapidly and a metal blade is applied to them to make the necessary adjustments. That's what leads to the little corkscrews of metal that I saw on my first day. Probasco remarked that when they're fresh off the wheel they are very hot and very sharp, so technicians take a lot of care to protect themselves and the machinery during the process.

So yes, trains get flat tires and it takes a team of dedicated professionals and some heavy duty equipment to get the problem fixed. And that's just a small part of what goes on at the Maintenance of Equipment building. The truth is the Valley Metro maintenance team is a seldom-seen but vital part of the company's mission to enhance lives and connect communities.

Alex Tsotsos
Rail Operations Communications Specialist
Writer, editor, musician, gamer, and former news professional. Frequently seen at Phoenix Rising matches and jogging around Gainey Ranch. May throw things in the presence of typos.