Maintenance work on west side MAX Blue Line may have late night riders doing a double take


Overnight work will create a better ride on the rails

A rail-grinding project underway on the MAX Blue Line between the Hatfield Government Center and the Robertson Tunnel may have late-night riders doing a double take. During the work, trains in both directions will only be using one track. Supervisors are on hand to safely monitor the train flow. Operators will make announcements at each stop.

The rail grinding began on Monday, Sept. 2 and had expected to be wrapped up by this Friday, but rain has led to delays. The work is now expected to last through Friday, Sept. 20 or possibly longer. The grinding needs to be done in the overnight hours, between about 11 p.m. and about 4 a.m., when few or no trains are running. Residents along the tracks from the Robertson Tunnel west to the end of the line in Hillsboro may hear the equipment during the work.

Grinding restores rail’s curved top

Wear and tear from regular train activity creates bumps on the rails and flattens out the profile or curve on top of the rail. Every year or so, TriMet brings in a piece of machinery called a rail grinder that looks similar to a small freight train. The grinder is equipped with stones underneath. It is run back and forth over a section of the track to grind away the bumps. For the current project, TriMet is bringing in a specific type of grinder that not only smoothes away the bumps, it also restores the curve on the top of the rail.

The grinding does generate sparks. Contract crews are following necessary fire watch precautions to suppress any sparks that may ignite.

End result? A better ride

This work, known as profile grinding, will result in a better fit between the steel wheels of the MAX trains and the rails. This will mean trains will sway less; the ride will be smoother and quieter. The grinding also reduces maintenance costs for the MAX system by extending the life of the rails.