Wheel-railhead force measurement system and method having cross-talk removed

A method for measuring the angle of attack in a set of wheels of a rail vehicle on track, the track having a shallow curvature, said method comprising:

• obtaining angle of attack data for each wheel in the set of wheels on the track having the shallow curvature at a position on the track,
• sensing position data at the position on the track, the sensed position data calibrated to railhead shape of the track at the position and weight of the rail vehicle at the position,
• removing cross-talk from the obtained angle of attack data based on the sensed position data,
• determining an angle of attack value based on the angle of attack data with the cross-talk removed.

A method for measuring the dynamic angle of attack for the leading and trailing sets of wheels in trucks of rail vehicles on track, said method comprising:

• determining raw angles of attack for all sets of wheels,
• removing cross-talk from the determined raw angles of attack,
• selecting only those raw angles of attack from the aforesaid step that have trucks on the track within a predetermined range of lateral to vertical force ratios wherein the selected trucks are properly steering trucks,
• calculating a dynamic angular offset value based on the selected raw angles of attack of the properly steering trucks,
• subtracting the calculated dynamic angular offset value from the raw angles of attack determined for all sets of wheels to arrive at a dynamic angle of attack for each wheel set.

A method for measuring the angle of attack for a set of wheels traveling over track having outside and inside rails, the method comprising:

• at a first point on the outside rail of the track measuring (1) vertical force with a first vertical sensor, (2) lateral force with a first lateral sensor (3) an outside angle of attack value with a first angle of attack sensor for the outside wheel at the time and (4) an outside position signal with a first position sensor when the outside wheel passes directly over the first point,
• at a second point on the inside rail of the track measuring (1) vertical force with a second vertical sensor, (2) the lateral force with a second lateral sensor (3) an inside angle of attack value with a second angle of attack sensor for the inside wheel and (4) an inside position signal with a second position sensor at the time the inside wheel passes directly over the second point, the second point located on a line perpendicular to a line tangent to the outside rail at the first point,
• measuring the speed of each set of wheels,
• determining a raw angle of attack for the set of wheels based on the speed and the outside and inside angle of attack values, the determined raw angle of attack having cross-talk removed based on the outside and inside position signals, wherein the outside and inside position data is based on calibrated data for known forces on the railhead,
• determining a ratio between the measured lateral force and the measured vertical force at the first point for the outside wheel,
• determining whether the ratio is within a predetermined range and, if so, averaging the raw angle of attack with all other raw angles of attack that have corresponding ratios within the predetermined range for other sets of wheels to obtain an average angular offset value,
• calculating a dynamic angle of attack for the set of wheels by subtracting the average angular offset value from each raw angle of attack to obtain a dynamic angle of attack value for the set of wheels.

A method for measuring the raw angle of attack for the leading and trailing sets of wheels in trucks of rail vehicles traveling over track having outside and inside rails, the method comprising:

• at a first point on the outside rail of the track measuring (1) vertical force with a first vertical sensor, (2) lateral force with a first lateral sensor (3) an outside angle of attack value with a first angle of attack sensor for each outside wheel at the time and (4) outside position signal with a first position sensor when the outside wheel passes directly over the first point,
• at a second point on the inside rail of the track measuring (1) vertical force with a second vertical sensor, (2) the lateral force with a second lateral sensor and (3) an inside angle of attack value with a second angle of attack sensor for each inside wheel and (4) an inside position signal with a second position sensor at the time each inside wheel passes directly over the second point, the second point located on a line perpendicular to a line tangent to the outside rail at the first point,
• measuring the speed of each set of wheels,
• determining a raw angle of attack for each set of wheels based on the speed and the outside and inside angle of attack values, the determined raw angle of attack having cross-talk removed based on the outside and inside position signals wherein the inside and outside position signals are calibrated data for known forces on the railhead.