UST 02 - Rail examining train of the new generation
for use on european railways

The safety of the railway requires regular examination of the running rails, as well as analysis and evaluation of the data recorded by the rail examining train.
 

1. Structure of the rail examining train

On basis of the experience with the Ultrasonic Measurement Trains UST 76 and UST 96 EURAILSCOUT Inspection & Analysis bv developed a rail examining train of the new generation for use on European railroads for its clients, in order to supplement the present fleet.

The UST vehicles examine the rails of the Netherlands main Rail Network one to four times per year. All parts of the rails where defects were identified are afterwards tested by hand measurement teams / railtesters to validate the defects and to determine the action that needs to be undertaken.

The rail examining train UST 02, the newest member of EURAILSCOUT's train fleet, is a two-part rail train with an overall length of 41.1 m.

To ensure application on the European railway network, the vehicle gauge profile UIC-Mb 505 was taken as a basis. The examining train can be used on standard-gauge stretches, and is also adaptable for broad-gauge according to the client's wishes. The maximum travelling speed of the train is 120km/h. The UST 02 is powered by means of two propulsion units each consisting of a diesel motor and a hydrodynamic transmission with under-floor design.

The vehicle's brakes are disc brakes operated by brake pneumatics of the KE construction. In addition to this, a nearly wear-free dynamic brake in retarder form has been installed. The rail examining train is equipped with the modern GSM-Rail radio system for its use in Europe. To ensure interoperability the UST 02 is equipped with SiFa, PZB 90 and the Dutch ATB Railway Safety System.

The rail examining train UST 02 has been especially constructed to cope with the climatic conditions in Europe (- 25°C to + 40°C). Both vehicle sections are equipped with heating and air-conditioning according to the requirements of the UIC 651 concerning room temperatures to be maintained and air-change figures.

The rail examining train is equipped with two powered bogies on the steering-head sides and two running bogies each on the connected side of the train. The two running bogies include the sensors of the measuring system.

The wagon interior is equipped with work rooms, common rooms, storage room and sanitary areas.

Wagon section 1 includes driver's cabin 1, one sleeping room, storage rooms for technical instruments, water supply containers, kitchen, sanitary area and workshop. A water supply of approximately 1,000 litres is available for the kitchen and sanitary area. All sewage is conveyed to a central bioreactor.

Wagon section 2 houses a corridor in the transitional area, a spacious measuring room, water supply containers, the meeting room, space for 19'' racks, storage and driver's cabin 2.

2. Measuring systems, representation and storage of data, evaluation

The task of the rail examining train is the detection and quantitative analysis of rail damages in real time. For this, its devices include two different measuring systems, a ultrasonic measuring system and an eddy current measuring system. Both systems allow a comprehensive analysis of the tested rail sections by means of sensory registration, data processing and evaluation, thus making available the basis for maintenance which can be planned by the railway management.

2.1 Eddy current measurement system

By using the eddy current examining system, EURAILSCOUT is able to detect and evaluate defects near the surface in the running-edge area of the rail. This data is the basis for rail grinding works and can also be used to asses the quality of the carried out grinding action. The Eddy Current Measurement System covers an area of approximately 0.2 to 25 mm on the running-edge of the rail, with four sensors on each rail. Moreover, each rail measurement unit has its own four-channel eddy current examining device and a measuring calculator for data storage and evaluation.

A steering computer coordinates the individual components of the measuring system and functions as a cutting-point for the signals provided by the train and the Ultrasonic Measurement System. All components are connected by a high speed LAN. Using D-GPS (Global Positioning System), tacho encoders and special markers the measurement results are located very accurately. This facilitates a later location of the damage spots measured.

The Eddy Current sensors are guided independently of the ultrasonic measurement-head transmitters to be able to follow the wear profile of the examined rail. Due to the measuring range of the sensors and their arrangement along the running edge of the rail, an easy classification of head-checks according to the "RailTrack- Standard" is possible. In addition to this classification, a statement about depth of the head-checks can be made using the amplitude of the eddy current signals. In considera-tion of the different initial angles of the cracks, a measurable damage depth of approximately 2-3 mm results.

The examiner can supervise the quality of the measurement data on an inspection monitor during the measurement. This offers sufficient information to recognise the disturbance-free functioning of the measuring system. The data are automatically evaluated at the same time as the measurement data are recorded. At the end of the measurement trip, a list with the results of this evaluation is available.

2.2 Ultrasonic measurement system

The Ultrasonic Measurement System, of the third generation in use on the UST 02, was developed on the basis of Ultrasonic Measurement Systems which had already proved their reliability. EURAILSCOUT's demands on the design of the Ultrasonic Measurement System, with the aim of detecting as many track defects as possible, as well as achieving high productivity and reliability, are as follows:

• The doubling of the ultrasonic examining channels to 32 units,
• The possibility of online processing of the data,
• Data processing speed which would allow a theoretical measuring speed of 100 kph
• Preparation for a real-time classification of the defects detected,
• The possibility of remote supervision of the systems using GPRS and UMTS / 3G technology

These improvements made a considerable expansion of both hardware and software capabilities necessary. A new processor-architecture has been developed for the real-time detection and processing of the measurement data, based on the industrial PC-architecture. The operating system Linux is being used.

The signals are digitalised and processed at an early stage during the exami-nation trips, and all measurement results are consistently stored. The processing of ultrasonic measurement data requires that related data, e.g. track pro-files, kilometres travelled and detected track defects are summarised to form so-called clusters. These are evaluated and classified, partly automatically and partly manually by the ultrasonic examiner on the rail examination train.

The UST 02 Ultrasonic Measurement System offers the possibility of a broader automation of the classification process in real-time, through the consistent storage of measurement data.

The recognition of vertical cracks and squats in the rail-head is possible, thanks to the integration of a second measuring bogie in the rail examining train UST 02, the expansion of the ultrasonic channels to 32 units, as well as the use of new additional ultrasonic examining-heads.

The number of real-time markers - used for, among other things, communication between the different measurement systems - has also been increased to 32 units. Other real-time markers, e.g. tunnels, switches or railway crossings, are submitted by the vehicle driver. These serve to synchronise the different measurement systems with the Ultrasonic Measurement System.

Corresponding pictures of defects are durably stored on CD; reports and pictures of defects are transmitted on paper or digital data-carriers to the com-missioner within 24 hours. Furthermore, they can be issued in different lan-guages.

The UST 02 is operated by a team of qualified professionals who have experi-ence in different European countries.

4. Results

The advantages of the new rail examining train UST 02 are not only in the area of vehicle technology, but also in the means of measurement technology. Due to the construction of the propulsion, the brake system and the wagon body, it is possible to travel stretches with inclines of up to 40‰ and track-curve radii of 120 metres. The newly developed 32-channel Ultrasonic Measurement System, now in use, assures the detection of all track defects relevant to safety.

Through the combined further development of the Ultrasonic and Eddy Current Measurement Systems, while simultaneously optimising the systems specifically having to do with the vehicle, EURAILSCOUT B.V. has succeeded, with the rail examining train UST 02, in setting new standards of excellence in measurement precision and flexibility of use in the interests of its clients, the European railways.