軌道橫向力與縱向力.ppt

1、Chapter 28,Track-Train Dynamics,Problem Lateral Forces High Center of Gravity Cars Vertical Forces Loaded and Empty Cars,Types of Lateral Movement Lateral Bending and Bending Stress Lateral Movement Tilt or Twist,Lateral Phenomena,Train Action Derailment Wheel Climbing Rail Overturning Brake Action

2、assumes status of a long and flexible beam in compression, a relatively unstable state Quick take-up of slack in a long train can also exert lateral pressure,Train Action (Contd),Reverse Curves “Chording” the Curve Truck Hunting,Derailment Causes Operating Error (Transportation) Mechanical Error (Me

3、chanical) Track Error (Engineering) Or a Combination of Above, Conduct Root Cause Analysis ,L/V Ratio Ratio of the lateral component to the vertical component of the wheel load. As ratio increases, tendency to derail increases,Lateral Slip,Load Application Ballast Section Design L/V Track Restraint

4、Ratio,Track Design Factors,Train Forces,Car Weight,Problems from Modern Cars,Rock and Roll,More prevalent on jointed track Joints every 19.5 feet induced oscillation Car body springs have natural frequency of oscillation At speeds between 12 and 20 mph frequencies are additive If square joints bounce Solutions: Dont set sustained speed limits between 12-20 mph Use snubbing devices on cars Use CWR,Rock & Roll,Truck Hunting,Long Cars,Transportation Techno