Rail E-ssentials

Test Centre for Rolling Stock develops new testing scope: Electric arc measurement

TÜV SÜD Rail’s in-house inspection body has developed a new testing scope. In addition to its most recent scope, which deals with the dynamic interaction between pantographs and overhead contact lines, the Test Centre for Rolling Stock has now developed a second test method in conformity with the standard – electric arc measurement.

The Test Centre for Rolling Stock at TÜV SÜD Rail is accredited according to EN ISO/IEC 17025 and approved by the German Federal Railway Authority (Eisenbahn-Bundesamt, EBA) as an inspection body for railway-specific inspections.

One of its most recent areas of expertise deals with the dynamic interaction between pantographs and overhead contact lines. According to the EN 50317 standard, measurement of the contact force is one method for carrying out approval-relevant measurements on the pantographs of rail vehicles. This method, which was developed five years ago, measures the forces between the pantograph carbon strip and the contact wire during an on-track test. The arrangement of the sensors at high-voltage potential and the specific setup of the measurement instruments require relatively complex measuring equipment. In addition to this method, applied and continuously further improved by TÜV SÜD Rail, the company has now developed a second test method in conformity with the standard. By applying electric arc measurement, the inspection body now aims to measure the duration of electric arcs with defined wavelength and intensity of light on the roof of the locomotive up to the vehicle's maximum speed.

The measurement instruments needed had to be in compliance with the requirements of the standard, as well as rail- and weather proof. Extensive research showed that no such special sensor was available on the market. Given this, the department for track tests had to design the measurement instrument in-house. Parallel to contact force measurement at the customer's premises, the department continually changed the sensor setups and tested them in realistic test environment. Proceeding in this manner, the experts were able to identify and constructively exclude factors that interfered with measurement, such as electromagnetic fields or solar radiation. In addition, this approach allowed the experts to gain important know-how in a field of testing as yet undeveloped. The measurement solution, which is now available, fulfils all requirements of the standard. A single sensor can now be used to test rail vehicles for all relevant rail energy systems (1.5 and 3 kV direct current and 15 and 5 kV alternating current).

Traceable calibration of the sensors presented one last major challenge. The required calibration equipment was unavailable even at Germany's national metrology institute (Physikalisch-Technische Bundesanstalt, PTB). In spite of these difficulties, the experts found a way to calibrate the measurement instruments in conformity with the EN ISO/IEC 17025 standard. The test method, which can be applied in the future, is a further building block in the Test Centre's already extensive service offering and is now ready for accreditation.

Interested in learning more? Then do not hesitate to contact our expert:

Thomas Noack
Test engineer
TÜV SÜD Rail GmbH
Test Centre for Rolling Stock / TR-RT/HAL
Eisenbahnstr. 3
06132 Halle (Saale)
Germany

Email: [email protected]