GB/T 25021-2010Track inspection car (English PDF)

3.1 Terms and definitions

For the purposes of this standard the following terms and definitions apply.

3.1.1 track geometry parameters: the parameters describing the geometric form of the track, including profile, alignment, gauge, cross-level (superelevation), twist and curve radius.

3.1.2 track characteristics value: the numerical value expressing the geometric quality of the track after the track geometry data have been assessed or computed in accordance with the relevant standards.

3.1.3 gauge: the smallest distance between the running edges of the two rails, measured within 16 mm below the running surface of the rail head.

3.1.4 alignment: the lateral irregularity of the gauge point on the inner side of the rail along the length of the track.

3.1.5 profile: the vertical irregularity of the top surface of the rail along the length of the track.

3.1.6 super-elevation: the height difference of the top surfaces of the left and right rails relative to the horizontal plane in the same cross section.

3.1.7 crosslevel: the height difference of the top surfaces of the left and right rails relative to the horizontal plane in the same cross section, excluding the superelevation value and the superelevation run-off set out for a curve.

3.1.8 twist: the torsion of the top surfaces of the left and right rails relative to the plane of the track, expressed as the algebraic difference of the cross-level values over a given base length.

3.2 Symbols

The following symbols apply in this standard.

3.2.1 A1: a wavelength of 3 m to 25 m.

3.2.2 A2: a wavelength of 25 m to 70 m, used to measure long wavelength irregularity limits. It is normally considered only where the line speed is greater than 120 km/h.

4.1 General requirements

4.1.1 The vehicle of the inspection car shall comply with the relevant requirements of GB/T 12817-2004. The interior materials of the inspection car shall comply with the relevant requirements of TB/T 3138-2006 and TB/T 3139-2006.

4.1.2 The strength design shall comply with the provisions and relevant requirements of TB/T 1335-1996.

4.1.3 The dynamic performance of the vehicle shall comply with the provisions and relevant requirements of GB/T 5599.

4.1.4 The outline of the vehicle, including the inspection equipment and sensors mounted on it, shall not exceed the requirements of vehicle gauge 1A and vehicle gauge 1B specified in GB 146.1.

4.1.5 The inspection car shall be able to inspect in both directions, and within the range given in the technical specification the results of the track geometry measurement shall not be affected by speed or by direction of travel.

4.1.6 The track inspection system comprises the track geometry parameter measuring subsystem, the car body vibration acceleration measuring subsystem, the rail profile measuring subsystem, the rail corrugation measuring subsystem and the environment monitoring subsystem. Of these, the track geometry parameter measuring subsystem and the car body vibration acceleration measuring subsystem are mandatory; the rail profile measuring subsystem, the rail corrugation measuring subsystem and the environment monitoring subsystem are optional.

4.2 Vehicle equipment

4.2.1 Air conditioning equipment shall be fitted, meeting both working and living conditions.

4.2.2 Electric or oil-fired heating equipment shall be fitted.

4.2.3 In addition to the normal lighting, emergency lighting shall be fitted in the inspection car.

4.2.4 The car shall be equipped with a distribution cabinet, an air conditioning control cabinet, a diesel generator control cabinet, an axle temperature alarm, a direct current charger, a direct current distribution surge arrester unit, a DC48V inverter of 5 kW output, an isolating transformer, an earth leakage protector and a vehicle safety monitoring device. The capacity of the direct current charger shall meet the requirement of charging the storage battery and the starting battery of the diesel generator set (DC48V, DC24V or DC12V).

4.3 Power supply equipment

4.3.1 Two diesel generator sets shall be fitted, the rated power of a single set being not less than 32 kW at an output voltage of AC380V/50Hz.

4.3.2 A maintenance-free alkaline battery of DC48V and a capacity of not less than 300 Ah shall be fitted under the car.

4.3.3 An uninterruptible power supply of not less than 5 kW able to work continuously for not less than 2 h shall be fitted on the car, using maintenance-free alkaline batteries.

4.3.4 Both ends of the vehicle shall be provided with the AC380V and DC600V dual train supply systems.

4.4 Inspection equipment

4.4.1 None of the inspection equipment mounted under the vehicle of the inspection car may affect the running safety of the vehicle, and the fatigue strength of all under-frame suspension arrangements of the inspection equipment shall meet the requirements of the relevant standards.

4.4.2 All the electrical equipment inspected shall have good electromagnetic compatibility and shall comply with the relevant provisions of TB/T 3034-2002.

5.1 Technical indices

The technical indices of the track geometry parameter measuring subsystem are given in Table 1.

Table 1 requires a gauge measuring range of 1 420 mm to 1 485 mm with a resolution of 0.2 mm and an accuracy of plus or minus 0.8 mm; alignment ranges of plus or minus 50 mm for wavelength A1 and plus or minus 100 mm for A2, with a resolution of 0.2 mm and accuracies of plus or minus 1.5 mm for A1 and plus or minus 4 mm for A2; profile ranges of plus or minus 50 mm for A1 and plus or minus 100 mm for A2, with a resolution of 0.2 mm and accuracies of plus or minus 1 mm for A1 and plus or minus 3 mm for A2; superelevation (cross-level) of plus or minus 225 mm with a resolution of 0.5 mm and an accuracy of plus or minus 1.5 mm; twist of plus or minus 100 mm; speed of 0 km/h to 250 km/h with an accuracy of plus or minus 1 per thousand; mileage of 0 km to 9 999 km with an accuracy of plus or minus 2 per thousand; line markers on the inspected line, including level crossings, turnouts, bridges and curve stakes; and a curve radius of less than 10 000 m with an accuracy of plus or minus 5 per thousand.

The notes to Table 1 state that either of the two space curves for wavelengths A1 and A2 may be selected; that the base length for twist may be chosen in the range 1 m to 18 m; and that where the curvature and the versine are measured at the same time the system shall be able to detect the start and end positions of the curve, including the positions of the straight-to-transition point, the transition-to-circular point, the circular-to-transition point and the transition-to-straight point, the position error of which shall not exceed 5 per thousand of the corresponding curve radius.

5.2 Technical requirements for the data processing part

5.2.1 Technical requirements for the data acquisition and synthesis part. 5.2.1.1 The inspection data shall be acquired and processed in real time, the track geometry parameters being output at intervals of 250 mm. 5.2.1.2 The system shall be able to store the raw sensor data and the track geometry parameters, the storage capacity for track geometry parameters being not less than 100 000 km. 5.2.1.3 The system shall be able to correct the mileage information automatically and manually. 5.2.1.4 The track geometry parameters output shall remain synchronised in spatial position.

5.2.2 Technical requirements for the data application part. 5.2.2.1 The track geometry parameters and the track characteristics values shall be stored and managed by means of a database. 5.2.2.2 The system shall be able to display and replay the waveform in real time and to compare it with historical data; the waveform shall be capable of real-time output and printing. 5.2.2.3 The system shall be able to edit the over-limit data in real time. 5.2.2.4 The track characteristics values shall be output in the specified format. 5.2.2.5 The raw sensor data and the track geometry parameters shall be capable of being replayed afterwards.

10.1 General

Testing and acceptance covers the acceptance of the vehicle of the inspection car and the acceptance of the inspection system. The acceptance of the vehicle is carried out according to the relevant vehicle technical specifications and is not dealt with in this standard. The acceptance of the inspection system comprises laboratory acceptance and field acceptance. Laboratory acceptance covers gauge, superelevation (cross-level) and the lateral and vertical vibration acceleration of the car body. Profile, alignment, twist and the other inspected parameters are accepted in the field.

10.2 Laboratory acceptance

10.2.1 Gauge laboratory acceptance. 10.2.1.1 Test items: the items shall include the measuring range, the resolution and the accuracy, and the measurement results shall meet the technical index requirements for the gauge parameter. 10.2.1.2 Gauge measuring range: two short rails are selected and the position at a gauge of 1 435 mm is taken as the origin; one side is then moved inwards and outwards in turn until the gauge measuring range is covered. On repeated measurement the results shall meet the technical index requirements for the gauge parameter. 10.2.1.3 Measurement of the gauge resolution: the single rail is moved slowly and, when the measured value changes for the first time by 0.2 mm, the position of the short rail is recorded; the short rail is then moved slowly again in the same direction and, when the measured value changes by a further 0.2 mm, the distance moved by the short rail is measured and compared with the value measured by the system to determine the resolution. 10.2.1.4 Gauge accuracy: the single rail is moved to a given position, the gauge is measured and compared with the standard value of that position (the accuracy of the standard value being not greater than 0.2 mm) to obtain the accuracy. The test is repeated at not less than five positions and the results shall all meet the gauge accuracy requirement. At the 1 435 mm position, observation is carried out for 30 min, fifteen sample values are taken at random and their accuracy is calculated; all shall meet the gauge accuracy requirement.

10.2.2 Cross-level and superelevation laboratory acceptance. 10.2.2.1 Test items: the items shall include the measuring range, the resolution and the accuracy, and the measurement results shall meet the technical index requirements for the cross-level and superelevation parameters. 10.2.2.2 Superelevation measuring range: a length of standard track panel is selected and the position at which the panel is horizontal is taken as the origin; the height of one side of the panel is then raised and lowered until the superelevation measuring range is covered. On repeated measurement the results shall meet the technical index requirements for the superelevation parameter. 10.2.2.3 Measurement of the cross-level resolution: the height of the panel is changed slowly and, when the measured value changes for the first time by 0.5 mm, the panel height is recorded; the panel height is then changed slowly again in the same direction and, when the measured value changes by a further 0.5 mm, the height through which the panel has moved is measured and compared with the value measured by the system to determine the resolution. 10.2.2.4 Cross-level accuracy: the panel is moved to a given position, the cross-level is measured and compared with the standard value of that position (the accuracy of the standard value being not greater than 0.3 mm) to obtain the accuracy. The test is repeated at not less than five positions and the results shall all meet the cross-level accuracy requirement. At the 0 mm position, observation is carried out for 30 min, fifteen sample values are taken at random and their accuracy is calculated; all shall meet the cross-level accuracy requirement.

10.2.3 Laboratory acceptance of the lateral and vertical vibration acceleration of the car body. The measuring range and the frequency response of the acceleration sensor shall meet the requirements for measuring the lateral and vertical vibration of the car body. The measuring accuracy of the sensor shall be not worse than plus or minus 0.01 metres per second squared and its resolution not worse than 0.001 metres per second squared. The measuring frequency range, the accuracy and the resolution of the acceleration measuring system are verified by determination on a standard vibration table.

10.3 Field acceptance

10.3.1 Accuracy and repeatability acceptance. The accuracy acceptance mainly verifies the degree of deviation of each measured item from the actual value. The repeatability acceptance mainly verifies the stability of the inspection system itself.

10.3.2 Method of acceptance. 10.3.2.1 Test line measurement: track geometry irregularities of each type are pre-set on the test line. Table 3 gives the accuracy of the pre-set track geometry irregularities: 0.2 mm for gauge, 0.3 mm for profile, 0.3 mm for alignment and 0.3 mm for cross-level. The inspection car runs in the forward and the reverse direction, and inspection is carried out three times at each of the speeds 40 km/h, 60 km/h, 80 km/h, 100 km/h, 120 km/h, 140 km/h, 160 km/h and 200 km/h. The inspection results are analysed for repeatability: counting all the inspection results at each pre-set point, the repeatability is regarded as acceptable when the measurement results satisfying the accuracy requirement account for 95 per cent or more of all the inspection results. 10.3.2.2 Measurement on an operating line: inspection is carried out on an operating line and, according to the circumstances, three over-limit records of each type of track irregularity are selected and rechecked on site. The inspection data are analysed for the rate of misjudgement, and the result shall meet the requirement that the rate of misjudgement be less than 2 per cent. The rate of misjudgement is the number of over-limit points not found on site divided by the number of over-limit points rechecked on site, expressed as a percentage.

10.3.3 Reliability verification test on an operating line. The purpose is mainly to examine whether the inspection system satisfies the requirements for ambient temperature, climatic conditions, stability in long periods of continuous work and reliability of the system. The inspection car inspects continuously over 5 000 km; the system is required to be stable and reliable and to meet the requirement for the rate of missed detection, which shall be less than 1 per cent. The rate of missed detection is the missed inspection mileage divided by the inspection mileage, expressed as a percentage.