TriMet and the Transit Police Division want to find the person or persons responsible for an incident that damaged a MAX train Thursday morning.

At about 5 a.m. a Blue Line train heading into the Millikan Way MAX station ran over a large rock that was in the eastbound trackway.

A hydraulic line on one of the train’s cars was damaged and the train had to be removed from service.

On closer inspection two large rocks were found that were about 12 inches in diameter.

There were passengers on the train, but no one was hurt.

There are no rocks along the tracks in that area that could have naturally fallen.

TriMet is asking anyone with information about the incident or who might have seen someone in that area to contact TriMet security.