The Washington Metropolitan Area Transit Authority (Metro) selected Falls Church, Va.-based ENSCO Inc. to develop and construct a special rail car known as a track geometry vehicle, which is used to inspect track conditions and identify any possible flaws.

A track geometry vehicle is an automated track inspection vehicle that can test several geometric parameters of the track without obstructing normal passenger rail service. The parameters generally measured include track position, curvature, distance between the rails, alignment, smoothness, and the cross level of the two rails. The vehicle uses a variety of technological sensors, measuring systems, and data management systems to create a profile of the track being inspected.

The new track geometry vehicle will allow Metro to conduct more comprehensive and frequent track inspections throughout the entire 106-mile Metrorail system during the day and when the system is closed. It will allow Metro to secure data and identify any areas where major repairs might require immediate attention, such as the identification of cracks or other flaws in the running rails or third rail.

Currently, track geometry testing of the 106-mile rail system is conducted several times a year by an outside contractor using hi-rail vehicles after the rail system closes for the night. When the hi-rail vehicle detects a worn-out piece of track, Metro officials replace it.

In addition to the overnight testing, track inspectors also visually inspect the rails twice a week to ensure the reliability and safety of the rail system.

The $7.8 million track geometry vehicle is expected to be on site in spring 2012.