Engineers in Germany are using a wireless, cloud-supported network of sensors to dramatically enhance the safety of rail systems by detecting damage in advance.

The cloud-based sensor system, which is currently being developed in Berlin by the Fraunhofer Institute for Reliability and Microintegration IZM, entails the installation of tiny radio sensors on the axles and undercarriages of trains in order to obtain data on the condition of parts which are susceptible to erosion and wear.

This data is then conveyed by means of wireless transmission to an online maintenance cloud, where it can subsequently measured and analysed.

The advanced wireless sensors are capable of performing what engineers refer to as “in-depth diagnosis” because of their heightened sensitivity, which enables them to detect even the slightest change in vibrations which could arise from something as small as a scratch on a ball bearing.

While wired sensors are already being used to detect wear and tear on rail vehicle chassis, the developers of the new system are pushing the diagnostic quality standards for the devices to a new level.

This enhanced sensitivity provides a far more accurate means of detecting faults and defects than other inspection methods, such as visual checks, which are never 100 per cent reliable. The sensors can warn engineers of potential damage long before it arises, thus enhancing the safety of the overall rail system, as well as the convenience and cost of repairs.

For example, the new method enables engineers to precisely determine how many months an axle bearing can still be put to use, removing the need to replace it prematurely to be on the safe side, which wastes the remainder of its service life and incurs needless cost.

Another key advantage of the new approach is that the wireless sensors enable engineers to monitor and inspect trains while they are still in service instead of having to wait until they are sitting stationary on the rail yard.

The use of the cloud facilitates the sharing of diagnostic information, which is a key priority if data is to be utilised and process in the fullest way possible. Cloud-based delivery of information enables train drivers to access data about critical wheel damage while operating vehicles and diagnostic technicians to assess the extent of gear damage when performing repairs. It also provides engineers with a slew of invaluable statistical information for improving future technical designs.

Other advantages of the system include the ease with which the wireless sensors can be retrofitted onto vehicles and their ability to harvest energy from the vibrations and heat of the parts they measure, thus prolonging their independent operating life.

The sensors can also readily adapt to the varying rotational speeds of different parts, thus permitting them to gather accurate data on performance irrespective of the speeds at which trains are travelling.

IZM hopes to test a prototype system with a tram operated by the city Brandenburg an der Havel within the next several years, before applying it to other rail systems in Germany.