摘要: |
A major constraint for higher-speed freight trains is truck hunting, or lateral instability. The three-piece truck, a workhorse for the railroad industry for over 100 years, is inherently susceptible to hunting in empty car conditions above 45 to 50 mph. This speed limitation on any train that has an empty car leads to operations restricted below the hunting speed. The Federal Railroad Administration, through the U.S. Department of Transportation Small Business Innovative Research (SBIR) Phase I program, sponsored the development of a Higher-Speed Truck (HST) for freight trains. The major objective was to develop a concept, which would raise the hunting speed of a freight truck to 150 mph without compromising the performance in other regimes. From this intense effort, a concept for a higher-speed freight truck intended for 70-ton regular freight was developed. The truck utilizes a rigid frame (H-frame) and an independent, compliant, primary suspension (springs/damping between the wheel-set/bearing adapter and the frame) for its basic architecture. Constant contact side-bearings and yaw dampers were added to improve dynamic performance. |