Gage Restraint Measurement System Comparison Tests: Railbound and Hi-rail Vehicles

Comparative tests were conducted to evaluate the gage restraint measurement system (GRMS) testing capabilities of a railbound GRMS vehicle, Federal Railroad Administration?s (FRA?s) T-6, and a hi-rail vehicle, Holland Company?s TrackStar GRMS system. The test objectives were to compare the performance of the two vehicles by monitoring the testing capabilities over the same section of track; evaluate repeatability and accuracy; and assess comparative vehicle performance over known defects. The tests were conducted on track owned by Maryland Midland Railroad, classified as FRA Class 2 track. Test data for both vehicles were analyzed with respect to FRA loading and gage restraint standards for GRMS testing and the requirements stated in the American Railway Engineering and Maintenance of Way Association (AREMA) Manual. Loaded and unloaded gage, delta gage, gage widening ratio, and projected loaded gage at 24 kips (PLG24), along with the left and right vertical and lateral loads, were the primary values analyzed and compared for the two vehicles. Results from these tests and related analyses indicate that both vehicles meet FRA and AREMA testing requirements. Accuracy and repeatability for both vehicles were acceptable. Data as recorded from each vehicle, analysis procedures, and conclusions are described in this report.