Method and apparatus for determining the operating speed of a rail vehicle

Apparatus for producing a speed reference for a rail vehicle having a rotatable wheel and axle assembly, said apparatus comprising:

• laser source means for directing a laser beam on a selected portion of said rotatable wheel and axle assembly;
• magnetic encoding means for impressing a magnetic signal on said selected portion of said rotatable wheel and axle assembly;
• magnetic receiving means displaced from said magnetic encoding means by a selected angular displacement for detecting the presence of said selected portion;
• processing means in electrical communication with said magnetic encoding means and said magnetic receiving means for deriving said speed reference based on an angular velocity of said selected portion of said rotatable wheel and axle assembly;
• and
• erasing means angularly displaced from said magnetic receiving means for removing said magnetic signal from said selected portion of said rotatable wheel after the presence of said selected portion is detected by said magnetic receiving means.

Apparatus for producing a speed reference for a rail vehicle having a rotatable wheel and axle assembly, said apparatus comprising:

• laser source means for directing a laser beam on a selected portion of said rotatable wheel and axle assembly, wherein said laser source means is situated to direct said laser beam to illuminate said rotatable wheel at a point generally in radial alignment with said magnetic encoding means;
• magnetic encoding means for impressing a magnetic signal on said selected portion of said rotatable wheel and axle assembly;
• magnetic receiving means displaced from said magnetic encoding means by a selected angular displacement for detecting the presence of said selected portion, said magnetic receiving means including a first magnetic receiving head angularly displaced from said magnetic encoding means in a first angular direction, a second magnetic receiving head angularly displaced from said magnetic encoding means in a second angular direction opposite said first angular direction, and whereby said apparatus is capable of determining said speed reference when said rail vehicle moves in forward and a reverse direction;
• processing means in electrical communication with said magnetic encoding means and said magnetic receiving means for deriving said speed reference based on an angular velocity of said selected portion of said rotatable wheel and axle assembly;
• and
• erasing means for removing said magnetic signal from said selected portion of said rotatable wheel after the presence of said selected portion is detected by said magnetic receiving means.

Apparatus for producing a speed reference for a rail vehicle having a rotatable wheel and axle assembly, said apparatus comprising:

• laser source means for directing a laser beam on a selected portion of said rotatable wheel and axle assembly;
• magnetic encoding means for impressing a magnetic signal on said selected portion of said rotatable wheel and axle assembly;
• magnetic receiving means displaced from said magnetic encoding means by a selected angular displacement for detecting the presence of said selected portion;
• processing means in electrical communication with said magnetic encoding means and said magnetic receiving means for deriving said speed reference based on an angular velocity of said selected portion of said rotatable wheel and axle assembly;
• said magnetic encoding means includes a first magnetic encoding head and a second magnetic encoding head displaced from said laser source means in respective first and second opposite angular directions;
• said magnetic receiving means comprises a first and a second magnetic receiving head displaced from said laser source means in said first and second opposite angular directions, respectively;
• wherein said first magnetic receiving head and said second magnetic receiving head are respectively situated outside of said first magnetic encoding head and said second magnetic encoding head with respect to said laser source means;
• and
• erasing means for removing said magnetic signal from said selected portion of the rotating wheel after the presence of said selected portion is detected by said magnetic receiving means.

A method of determining an operating speed of a rail vehicle, said method comprising the following steps:

• (a) directing a laser beam on a portion of a rotatable wheel and axle assembly of the rail vehicle to form an enhanced magnetically susceptible area thereof;
• (b) impressing a preselected magnetic signal on said magnetically susceptible area;
• (c) detecting the magnetic signal from said magnetically susceptible area during further rotation of said rotatable wheel and axle assembly;
• (d) deriving the operating speed of said rail vehicle based on a time differential between a first time when said magnetic signal is impressed on said magnetically susceptible area and a second time when the magnetic signal is detected from said magnetically susceptible area.

A method of determining an operating speed of a rail vehicle, said method comprising the following steps:

• (a) directing a laser beam on a portion of a rotatable wheel and axle assembly of the rail vehicle to form an enhanced magnetically susceptible area thereof;
• (b) impressing a preselected magnetic signal on said magnetically susceptible area;
• (c) detecting the magnetic signal from said magnetically susceptible area during further rotation of said rotatable wheel and axle assembly;
• (d) deriving the operating speed of said rail vehicle based on a time differential between a first time when said magnetic signal is impressed on said magnetically susceptible area and a second time when the magnetic signal is detected from said magnetically susceptible area;
• and
• (e) erasing said magnetic signal from said enhanced magnetically susceptible area.