Improved communication of condition monitoring data brings benefits. By Nicola Anderson

As investment in rail infrastructure continues to increase, digitalisation is emerging as a key driver for innovation across the sector, globally and in the UK. These improvements are bringing many benefits – for example, providing delay data to passengers and real-time traffic management systems for drivers.

With rail passenger numbers on the rise in the UK and placing extra pressure on capacity, demand for more predictable and reliable rail services is growing.

A significant cause of train delays is infrastructure faults; in particular those that result in unexpected maintenance, such as the upkeep of rolling stock, and rail repair procedures. The latest condition monitoring systems can help to reduce the negative effects of such ad hoc maintenance by predicting failures before they occur.

POM 160Condition monitoring systems typically collect readings from sensors at a range of locations on board the rolling stock itself, using them to provide an indication of status. The train operator can then incorporate the condition of the fleet into the maintenance plan. This leads to a reduction in the frequency of unexpected faults and helps to minimise delay times experienced by passengers.

However, there are limitations associated with current condition monitoring systems. The sensors record data at high frequencies, which means storage systems can become overloaded. The costs associated with the necessary transmission and storage of high-frequency data are high. Additionally, a large proportion of the generated data is redundant, as it is unlikely to deviate from one reading to the next.

Hitachi has been granted a UK patent for a solution to this particular problem. The patented technology collects sensor readings from a range of onboard equipment and produces a data packet for transmission to a ground-side database whenever one of the measured values changes.

The condition monitoring system has a central monitoring unit (CMU) to receive the sensor readings and communicate with the ground-side database. Additionally, the CMU makes health assessments based on the sensor readings and informs the driver about ongoing and potential issues on board the vehicle. The location of the sensors varies depending on the vehicle and journey type – freight or commuter for example. These locations may include temperature and vibration sensors at the wheels and speed sensors on the passenger doors.

After receiving data readings, the CMU compares the values with those taken the previous time. If a change is detected, the CMU produces a data packet including a timestamp, the current value, the preceding value and a unique identifier code.

Hitachi’s condition monitoring system is able to minimise the transfer of redundant data from the CMU to the ground-side database, helping to reduce pressure on transmission and storage systems. Not only does this help to decrease the risk of overloading, it also helps to improve the system’s operational efficiency.

For passengers, the main benefit of these advanced condition monitoring systems is likely to be a reduction in delays and disruptions to services. However, another potential benefit could be an improvement in their overall experience. For example, if high levels of vibration are detected in the vehicle’s suspension, maintenance can be undertaken immediately to mitigate the effect on passengers.

With patent protection secured, Hitachi benefits from an exclusive right to bring its invention to market and, potentially, license it to third parties. This period of exclusivity extends for 20 years, preventing competitors from copying its invention during this time.

Nicola Anderson is a patent attorney at European intellectual property firm, Withers & Rogers. She advises innovators in the rail sector about how to protect their inventions.