Derailment detecting method and derailment detecting apparatus for rolling stock

A derailment detecting method for rolling stock, which is applied to rolling stock having a truck which comprises wheels rolling on rails, and spring rigging, and a carbody to which said truck is attached, said derailment detecting method for rolling stock comprising:

• a step of detecting vertical acceleration at said carbody above said spring rigging during running of said rolling stock on said rails;
• a step of calculating a vertical displacement amount by double integral of said vertical acceleration every evaluating time, said evaluating time being defined as a time period from a start of descent of said carbody to arrival at half a height of said rails, in a free fall of one axle of said wheels by a distance equal to the height of said rails;
• and
• a step of determining that said rolling stock is derailed, in the case that said vertical displacement amount is negative and an absolute value thereof is not less than a predetermined reference value.

A derailment detecting apparatus for rolling stock, which is applied to rolling stock having a truck which comprises wheels rolling on rails, and spring rigging, and a carbody to which said truck is attached, said derailment detecting apparatus for rolling stock comprising:

• a limit acceleration storage for storing limit vertical acceleration defined for each of varied running velocities from a maximum of vertical acceleration in a predetermined frequency range at said carbody above said spring rigging, said vertical acceleration being detected at each of said running velocities while said rolling stock is made to travel on a predetermined route,
• a car velocity detector for detecting real running velocity of said rolling stock traveling on said route;
• an acceleration detector for detecting real vertical acceleration at said carbody above said spring rigging during traveling of said rolling stock on said route;
• a filter for extracting a component in said frequency range from said real vertical acceleration;
• and
• a determining part for determining that said rolling stock is derailed, in the case that an absolute value of the real vertical acceleration in said frequency range exceeds said limit vertical acceleration corresponding to said real running velocity.

A derailment detecting apparatus for rolling stock, which is applied to rolling stock having a truck which comprises wheels rolling on rails, and spring rigging, and a carbody to which said truck is attached, said derailment detecting apparatus for rolling stock comprising:

• an acceleration detector for detecting vertical acceleration at said carbody above said spring rigging during running of said rolling stock on said rails;
• an integrator for executing double integral of said vertical acceleration every evaluating time to calculate a vertical displacement amount, said evaluating time being defined as a time period from a start of descent of said carbody to arrival at half a height of said rail, in a free fall of one axle of said wheels by a distance equal to the height of said rails;
• and
• a determining part for determining that said rolling stock is derailed, in the case that said vertical displacement amount is negative and an absolute value thereof is not less than a predetermined reference value.