GRMS Vehicle T-18

T-18, the new FRA Gage Restraint Measurement System (GRMS) vehicle procured in May 2004, is a state-of-the-art deployable GRMS vehicle which utilizes a 5th split railroad axle to laterally load the head of both adjacent rails of railroad track in order to measure rail motion under a combined vertical and later load for the detection of weak ties and fasteners. It has a unique suspension system which maintains alignment and apply continuous loads perpendicular to the rails regardless of the roll, pitch or vertical movement of the carbody on its suspension, or the curvature of the track; lifts and lowers split axle for testing and stowage; and orients split axle so that wheels are tangent to rails as track curvature varies.

Deployable Split Axle GRMS
T-18 overcomes the limitations associated with the current T-6 thereby increasing the safety by:

Reducing the risk of derailment of GRMS vehicle by decoupling testing axle from the vehicle operational axle

Minimizing damages to GRMS hardware in the event of derailment by limiting test axle movement and quickly lifting test axle off the track

Allowing lateral and vertical load variations

Increasing system responsiveness with lighter test axle and lower bending moment

Allowing higher operating speed at non-testing mode

Minimizing data loss through switches.

With the advances in GRMS technology, T-18 testing speed could potentially increase above 35 mph without data quality degradation .