A red train that has stopped at the railway station.
Railway Defect Detection Methods (part1)

The train transport is the one of the important methods of transportation that transfers passengers and goods on tracked vehicles running on rails. The railway track comprises various equipment, including but not limited to rail, sleeper, ballast, track bed and so on. Indeed, the railway equipment is the basis of rolling stock and train operations that bears the pressure from the wheels of rolling stock. In order to ensure that the train can operate at an uninterrupted maximum speed, and the railway authorities anticipate a complete passenger and freight transportation at desirable quality, the railway lines must be kept in standard conditions. Considering, the continuous rolling of locomotives and long-term trainloads, which results is the track geometry of the railway line continues to deteriorate. Understandably the subgrade and ballast bed continue to produce deformed rails, couplings and sleepers, resulting in continuous changes in the technical status of the line equipment. In order to keep the railway line in standard conditions for a long period, regular maintenance and repair operations are required. Traditionally, the railway defect detection process, which is deemed difficult and dangerous, is done manually by the railway maintenance workers. In the recent years, more sophisticated equipment such as portable detectors, track inspection trolleys, track comprehensive inspection vehicles, etc. had been developed. This article outlines two main modes of inspection, namely static and dynamic inspection, which are commonly used in the railway defect detection and maintenance work. Furthermore, the railway inspection equipment used by the major countries is summarized and the impact on railway inspection based on deep learning and artificial intelligence is appropriately predicted.


Static inspection has changed from traditional manual inspection to new inspection methods, such as mechanical and electronic circuit inspectors and three-dimensional precision measurement systems. In the process of track static inspection, workers need to detect track gauge, track cross level, track alignment, etc.

Vibrations and the impact of high-speed trains are affecting track geometry to a huge scale. Besides heavy wear of the track, the track gauge, track cross level and track alignment are getting affected. The track geometry gauge is mainly used to measure the gauge and cross level (super elevation) of the line. Manual gauge is a traditional measure instrument. Manual gauge is usually used as measurement railway speeds of less than 160km/h. During the measurement process, many aspects, such as the checking time, the judgment standard of the personnel, the position of the observation, the placement of the instrument, etc, can affect the accuracy of the values. Therefore, this method is not suitable for high-precision high-speed railway line detection, and if there are occurrence of combination factors, as discussed above, it may affect the line status of ordinary-speed railways. Digital gauge is a new type of track geometry gauge. Comparing with the manual measuring methods, the digital gauge greatly improves the accuracy and eases the measurement work in track maintenance since it is equipped with records such as rapid numerical display, automatic temperature compensation, and an over-limit alarm. Therefore, in an environment where railway speeds continue to increase along with the work intensity, digital gauges provide easier and safer working environment. In daily maintenance, workers use the track geometry gauge to detect the gauge, track cross level, and super elevation. However, at present, the track geometry gauge can only complete some basic data detection, the workers need to consume a lot of physical energy, and the work efficiency is relatively low.

The geometric state detection of high-speed railway tracks is to detect the vertical and lateral deviations and irregularities of the track under the condition of no trainload, and the detection results are used as the main basis for track adjustment. It is a new technology to use the track inspection trolley to detect the geometric state of the track. It calculates the center mileage of the line by measuring the prism coordinates installed on the track inspection trolley. In the following, the railway  inspection  equipment  used  by  the  major  countries  are  summarized  and  the impact  on railway inspection:

1.1 GEDO CE:

The GEDO CE track inspection trolley produced by the German Sinning company, which has a mature and stable measuring system, is suitable for fine adjustment of double sleeper type ballastless track, turnout laying, long rail laying, joint adjustment and joint test, line maintenance, etc. GEDO has been widely used in the European railway industry. Its function into quickly collect line data, obtain the deviation between the design value and the measured value, and analyzing it through software. The data of the optimal starting amount and shifting amount are transmitted to the tamping machine in a digital way. At the same time, the tamping operation plan is designed to guide the accurate operation of the tamping machine. The GEDO CE test shows that when the equipment is in a static and moving state, the error of the measurement point data is very small. When the equipment is in different speed states, it adopts automatic mode to collect, the result shows that the error is very small. In summary, it is shown that GEDO CE performs well under various conditions and the data is stable.

1.2 Amberg:

Amberg GRP VMS adopts the relative measurement principle based on absolute control, which perfectly combines absolute measurement and relative measurement, and uses CPIII more efficiently, which can greatly improve the measurement efficiency while ensuring high accuracy. The system consists of a data collection car and a satellite car. In addition to integrate mileage, super-elevation and gauge sensors, the data collection car is also equipped with a control point measuring instrument, which can measure the horizontal and vertical distances from the track to the control point. The product has been tested by the German market and has mature performance. A radio modem can be used for data communication between the computer and the total station. The equipment has a stable performance and high accuracy. It is currently used by many companies in China and has been used in railway construction in countries along the “Belt and Road”.

1.3 SOUTH:

The SOUTH track inspection is made by China South Locomotive & Rolling Stock Corp. TGS FX standard hand-push type track inspection trolley assembled with sensors for track gauge measurement, track super elevation measurement and relative mileage measurement. It can automatically identify the target LEICA and other total stations, which can ensure the accuracy and reliability of the measurement. At the same time, the track inspection trolley has strong field operations and data processing capabilities. A radio modem can be used for data communication between the computer and the total station. The equipment has a stable performance and high accuracy. It is currently used by many companies in China and has been used in railway construction in countries along the “Belt and Road”.

1.4 Rail Defect Detector:

With the development of ultrasonic testing technology, ultrasonic testing technology has become the main method of railway track defect detection. European countries and Japan and other developed railway countries have successively launched various forms of ultrasonic rail defect detection equipment, including “portable hand-push defect detectors”, “automatic rail defect detection vehicle”, and “special rail defect detection train”. For more information, you can also read “Train Wheel Inspection with Ultrasonic Measuring System”.

ADOR Tech, with the help of its international partners, offers a full range of Non-Contact Measuring Systems for the Canada and US Railway Industries. For more information, don't hesitate to get in touch with us.