ODT 08 - overhead contact line inspection train

Modern contact-oriented and contact-free inspection and analysis of overhead contact line systems in the normal and high-speed area guarantees safe and trouble-free train operation.

At speeds of up to 80 km/h, the ODT 08 acquires the data for the entire overhead contact line systems. The diagnostic train is equipped with modern and innovative measurement and diagnostic techniques for the different tasks of inspecting overhead contact lines.

The integrated inspection and evaluation of the different parameters during a measurement run and the combination with the measurements from other infrastructure areas also possible with the diagnostic train result in considerable operating advantages and, at the same time, lower inspection costs than with conventional methods.

The ODT 08 of Eurailscout collects a multitude of infrastructure data required for a comprehensive analysis of the status and thus furnishes the basis for planning condition-oriented maintenance.

Overhead contact line measurement and inspection systems

Measurement of the overhead contact wire position

From the image data of contact-free laser systems, the height and lateral position of the overhead contact wires are determined, already corrected to account for the separately acquired rolling motions of the railcar body. The measurement of the height can be made either under load (pantograph in working position - contact pressure can be changed according to overhead contact line design) or without loading.

Determination of the overhead contact line mast positions

The position of the mast along the rails travelled is automatically recognised by laser-based systems and stored together with the measurement and inspection data. These positions are specified together with the corresponding evaluations.

The mast recognition system is comprised of two sensor units, installed at the left and right on the roof of the test coach, in the vicinity of the pivoted bogie. Each unit consists of two laser distance sensors. The measuring beams for the distance sensors are aligned vertically upwards. When the two laser beams of the sensor unit are reflected nearly simultaneously from an object, it is then assumed that the object is a lateral support and thus a support point for the overhead contact line.

Inspection of the catenary

Two high-speed diode scanning cameras positioned at the outer edges of the diagnostic train, in combination with infra-red laser lighting, continuously record images of the opposite sides obliquely from below with a resolution of 1 mm at 80km/h (45 µsec exposure time - 100 MHz data rate), resulting in an "infinitely" long, double-sided image of the catenary. The data are acquired exactly according to the mileage (km) markings. These high-resolution images enable visual inspection on the monitor screen (monitoring), without the need for further processing. In a further step, these images can be prepared for automatic evaluation.

Inspection of the cross-span elements

The two cross-span element sensors positioned at the ends of the diagnostic train enable the acquisition of the cross-span elements in and opposite to the direction of travel with high-speed scanning cameras.

The forward mast recognition system recognises the cross-span element and triggers the rear, forward-"looking" scanner system.

Taking into account the distance travelled, the forward, rear-"looking" scanner system is then activated. This records images of the cross-span elements from both sides. The individual images are recorded exactly according to the mileage (km) markings. These high-resolution images enable visual inspection on the monitor screen (monitoring), without the need for further processing. In a further step, these images can be prepared for automatic evaluation.

The scanners deliver these images

in the direction of travel	and	opposite to the direction of travel

The automatic visual inspection is on the basis of the catenary and cross-span element systems. The four sensors of these two systems acquire 4 Gbyte image data per kilometre travelled. These data are compressed by real-time data compression to less than 3% of their original volume.

The inspection of the cross-span elements and the catenary is performed by the offline recognition of alterations on the basis of automatic image processing. This compares a defined reference state (learning run) with all following inspections. The reference data for the particular distance from the learning run are compared with the image data from the inspection runs. In this way, defects are recognised and accordingly classified.

The real-time determinations of the overhead contact wire height and lateral position and the thickness of the overhead contact wire are supplemented by offline image processing on the basis of the stored images.

The automatic image evaluation is performed with the aim of recognising damage and foreign objects. This concerns the automatic detection of defects such as loose or missing screws, splayed cables, and damaged components.

Display of the results of measurement and inspection

All geometrical data for the overhead contact line system described above are acquired every 5 cm or every centimetre, or at least every 10 cm or 25 cm and digitally stored. All image data can be displayed on computer monitors during the inspection run. The geometrical data can be transmitted to the IRISsys database. All additional data can be stored and analysed in the IRISsys. Adapting customer requirements to every international railway organisation is possible; the system utilises the most recent database technology, enabling the flexible importing of all measured and inspection data. Moreover, the system functions with an easily operated graphics-oriented user interface.

The image data from the inspection systems can be displayed via a separate viewer, according to the mileage (km) markings over the travel distance.

The results of comparing the images are shown by a special program in tabular form, together with the image details. The results protocol includes information on the location of the deviation, as well as the type and class of the defect.

Parameters

Overhead contact wire:

• Horizontal position (lateral position, zigzag)
• Vertical position (height)

Mast position

Inspection and video recordings

Automatic visual inspection of the catenary and cross-span elements

Your advantage

• Distinct limitation of damage by the early on recognition of defects
• Targeted elimination of defects
• Distinctly improved quality of the inspection results
• Annual cost savings for the inspection
• Computerised evaluation, verification and administration of the inspection
• Reduction of blockage times and occupation of rail sections for inspection activities