ARM Lands Long-Term ST Contract

Written by David C. Lester, Managing Editor, Railway Track & Structures
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Rail grinding and polishing at Sound Transit’s Northgate Station. ARM photo.

Seattle’s Sound Transit has awarded a multi-year, $24 million contract for rail grinding, polishing and engineering inspection services to Advanced Rail Management Corp. (ARM). The contract includes corrugation measurement and track geometry, ultrasonic and eddy current testing as part of the inspection and quality assurance requirements.

The five-year contract, which may be extended for five additional one-year terms, applies to Sound Transit’s existing Link Light Rail, as well as new line extensions, including the I-90 floating bridge across Lake Washington.

Click here for more information on the I-90 floating bridge.

Sound Transit’s contract “is among the most comprehensive rail assessment and maintenance contracts awarded by a North American transit agency,” aid ARM President Gordon Bachinsky. “This ground-breaking contract is the first of its kind in North America to require rail polishing that adheres to customized acoustic requirements that are based on the ISO 3095 standard, which is considerably more demanding than the EN 13231-3 standard that North American railroads and transit systems typically grind to. Sound Transit’s approach to looking after rail integrity, wear, and noise and vibration generated by the rail surface finish has resulted in achieving a high level of standards compared to other North American rail systems in the realm of rail grinding and maintenance programs.”

To achieve Sound Transit’s goals, ARM and project consultant National Research Council of Canada will implement a “gradual-preventive” grinding program. ARM will have access to a variety of hi-rail and railbound rail grinding equipment fitted with coarse to extra-fine-grit grinding stones, depending on metal removal and surface finish requirements. Milling equipment will also be available if needed to address surface damage requiring extensive metal removal.

To prepare for the grinding/polishing program, ARM and its consultants will conduct a comprehensive inspection to quantify rail surface conditions on the system. Measurement will include:

• Systemwide track geometry testing of all typical parameters, such as curvature, gauge, profile, alignment, etc. It will also include optical rail profile measurement.

• Ultrasonic testing (UT), which will identify internal rail defects, including detail fractures from shelling, broken or fractured rail base, defective plant or field welds, bolt-hole cracks, etc., by type, size, and location. Squats and surface cracks that are identified by the UT test vehicle will be verified by hand tests.

• Pre- and post-grind eddy current testing, which will measure surface crack length, depth, and geometry; proximity to other cracks; and electromagnetic properties of the rail base material. Reports will include measurements, graphs, images, and trending reports; defects will be color- coded to distinguish the severity.

• Corrugation measurement collected by a Corrugation Analysis Trolley (CAT), including roughness measurements that reference the guidelines of ISO 3095.

Corrugation Analysis Trolley (CAT). ARM photo.

ARM will use data from these measurements to prioritize locations, estimate metal removal and the number of passes that will be required, and determine the total number of miles to be addressed in order to establish “an effective gradual-preventive grinding program,” the company noted. “Corrugation measurement data will be used to guide rail polishing efforts to meet Sound Transit’s 5-micrometer surface roughness target within the wheel/rail running band.”

“Sound Transit’s grinding and polishing acceptance criteria will ensure that the wavelength signature of the finished rail will mitigate the types of noise and vibration-related problems previously encountered on the system,” said ARM Director of Business Development & Projects Mark Reimer.

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