Aiming at the irregularity of track gauge existing in the current track

a real-time dynamic detection system for the gauge installed on the track inspection vehicle is designed. The system determines the sampling period and sampling point of the 2 D laser displacement sensor according to the number of pulses emitted by the shaft angle encoder and realizes the synchronous data acquisition of the sensor. The transmission of the rail profile data is completed by the controller area network（ CAN） protocol-based transmission bus. The upper computer Lab VIEW application program records gauge point coordinates

and the gauge value is calculated according to the basic formula of the trigonometric function and stored in the Excel table. Through system and manual field test

the system hardware performance stability and software design rationality are verified

and the purpose of dynamic realtime detection of gauge distance is achieved. When the track inspection speed is 30 km/h

the error of the gauge detection is between（-0. 85

+ 0. 65） mm. The system has the characteristics of high efficiency and versatility

and has certain reference value for other data acquisition systems.