ARM Lands MBTA Rail-Measurement Contract
The contract, which includes collection of rail profile, vertical, gauge-face and combined wear, percentage of head loss, gauge and field lip, track gauge, cross-level, cant angle, and gauge-face angle data, requires semi-annual testing on the Green Line and annual tests of the Red, Orange and Blue lines. In all, ARM will collect 173 track-miles of data per year.
Data will be captured at 6-inch intervals on the Green Line and 12-inch intervals on the other lines—the tightest data-collection-interval requirements in North America. The locations of track features such as switches, lubricators, passenger platforms, tunnels, bridges, and the beginning and end of each curve will be identified and shown on reports, according to the MBTA chain-marker system.
Among the more challenging aspects of the data collection—beyond the steep (7%) grades and double-restrained, 75-foot radius curves—is the precise gauge-face angle data required on the Green Line, which, due to the short (3/4-inch) wheel flange on the Green Line cars, is subjected to additional scrutiny and bi-annual testing.
“We developed a custom algorithm to more precisely capture gauge-face angle measurements,” ARM President Gordon Bachinsky said. “This allows the MBTA to monitor change to the gauge-face angle between measurements and to develop wear trends over time.”