About once a week all the rail in the Plymouth area is inspected. This generally begins after the traffic cleans up on monday and usually finishes up on wednesday. During the daylight hours train traffic is sparse as the track inspectors roam the area in the Hi-Railers. They visually check for obvious faults in the track structure and roadbed.

Track inspection HiRailer heading North on the Saginaw Sub at Middle River.

Periodically more sophisticated methods are employed to find internal structural defects hidden in the metal. Using electrical inductance or SONAR techniques to expose the defects rail inspection services are usually employed under the guidance of the track inspection department.