An initial interim report shows that the digital status monitoring for rail vehicles detects maintenance-relevant errors earlier, with more precision and more potential savings, compared to the previous system. Passengers and residents alike benefit from more safety and comfort. Thanks to the positive results, the partners want to expand their cooperation as planned.
ZF's modular condition monitoring system monitors the condition of the rail tracks and wheels using Bluetooth-connected sensors on the vehicle bogie. Based on daily measurement data such as acceleration and vibrations, damage can be detected early on via cloud computing, contributing to early fixes. This reduces downtime and helps keep public transport running efficiently.
Wolfgang Malik, CEO of Holding Graz, said: "The Holding sees everywhere its task in optimizing the use of resources and the quality factors of urban living spaces in Graz. The application of alternative energy, innovative drive technologies and an environmentally oriented traffic management from all levels are our top priorities. Therefore, I am proud that, in cooperation with the global technology company ZF Group, intelligent sensors that can be used in the entire line network have been developed for efficient, emission-reduced tram operation.”
The Graz Linien system currently focuses on so-called flat spots – uneven wear on the steel tyres of the vehicles. Such wear means that the wheel no longer rolls gently over the rail, but slides or slips on the track. Passengers and bystanders can usually hear and feel rumbling while the train is in motion. With increased wear, further damage to the wheel and rail is possible.
But the safety of passengers and vehicles was not the only reason for Graz Linien to focus on this source of error. Residents also complained about noise. An initial attempt to detect flat spots using a stationary measuring system did not produce the expected success.
Markus Gross, head of ZF's rail drive systems product line, said: “Together with Graz Linien, we designed our system to detect this type of error source early on and precisely. Only the installation of "connect@rail" provided the necessary information on the existing flat spots. Together with ZF, Graz Linien can now reduce consequential damage, as well as stress and comfort restrictions for people and environment.
After a promising pilot phase in 2019, Graz Linien and ZF signed a cooperation agreement for continuous operation, initially in ten vehicles on eight lines. During the first measurement period from December 2020, eight flat spots were correctly identified and rectified immediately after occurrence. Moreover, since the system was put into operation, no flat spots have been overlooked in the ten equipped vehicles. A system update at the end of March increased the quality of the predictions even more, said ZF.
"With connect@rail, our repairs can be planned based on daily updates, thus reducing noise for the residents to a minimum. We save material and costs because we can turn the wheels in a targeted manner," said Thomas Kerschberger, division manager for workshops at Graz Linien. "In addition, we detect conspicuous vehicles early on, which we can then inspect in detail." In fact, the system was triggered in one tram particularly often; the ZF system assisted in troubleshooting, and corresponding repair work could be initiated.
ZF and Graz Linien jointly presented the comprehensive results in Graz on June 16, 2021.
Graz Linien and ZF have already signed an agreement for further cooperation. Another 10 vehicles will be equipped with "connect@rail".