Train travel remains a vital aspect of the overall transportation mix in the UK. According to the most recent report from the Office of Rail and Road (ORR) a total of 285 million rail passenger journeys were made in Great Britain in the latest quarter (1 October to 31 December 2021) – more than double the 139 million journeys made in the same quarter of 2020, equating to 61.8 per cent of the 461 million journeys made in the same quarter in 2018.

Given the electrification of the train network, the role of the pantograph – which sits on top of the train collecting electricity from the overhead line equipment (OLE) – remains crucial to safe and secure rail travel.

The pantograph needs to be properly connected to the OLE in such a way that it is set within the right range to collect electricity and keep the train running. A faulty pantograph connection may lead to unpredictable repair work and misery for passengers who may have to endure delayed and disrupted journeys. Indeed, damage to the pantograph and OLE could affect the rail company’s reputation in the eyes of customers.

The pantograph head is used in very harsh weather environments and its carbon strip rubs along the overhead contact wire at speeds of up to 125 mph. Although pantographs are set with a static upward force of typically 90 Newtons, they also contend with varying dynamic loads including aerodynamic forces for which the pantograph has to be balanced in both directions. Up to 300 amps may be transmitted at 25,000 volts between pantograph and contact wire with occasional arcing, which can be severe.

Repairing damaged pantograph/OLE on site can be a dangerous, difficult and expensive process for rail companies. It is therefore desirable to have a remote, on-board monitoring system to monitor the condition of the pantographs and inform engineers in advance of any maintenance that is needed that will avoid breakdowns when they are in operation.

To ease the problem, a research team led by Professor Tong Sun and Professor Ken Grattan has created a new smart pantograph which is less likely to suffer damage and can help rail engineers prevent trains going out of service. This saves money for the rail companies and ensures an easier journey for passengers.

Professor Sun, Professor Grattan and their research team worked with Faiveley Brecknell Willis, a world-leader in railway electrification based in the UK, to create a self-sensing pantograph for the rail industry. The pantograph fits onto existing electric trains, so no extra modification is required.

The researchers developed a system known as ‘Internet of Intelligent Pantographs (IIoP)’ to enable cost reduction of traditional pantograph/ OLE maintenance while increasing the efficacy of current approaches.

In order to enhance customer experience and reduce the number of pantograph related incidents in the UK (currently 7.5 per month) which adversely affect passenger services, the team pursued the approach of developing scalable technology to provide accurate measurements on this critical interface.

The system detects ‘hard spots’ and other indications of poor performance, such as loss of contact between the pantograph and contact wire, and reports such events in real-time. This then allows intervention to investigate, adjust or repair emerging defects before deterioration leads to catastrophic failure.

The continuous analysis of the dynamic interaction between pantograph and wire will allow trends to be identified resulting in earlier intervention, reduction of the build-up of wire and pantograph wear and extension of the time before large scale renewal becomes necessary.

Train fleet owners will have available comparative data between trains operating on the same route, making direct comparison of performance across the fleet possible. This will in turn provide information about individual pantographs and highlight those pantographs which are performing outside or below acceptable limits.

One of the main benefits of using IIoP is related to its capability to provide real time reporting of critical events to the railway asset owners to allow timely actions to be taken and ensure ‘incident-free’ electrified train operation. The reporting is provided via a digital and cloud-based user-friendly interface and this new, better and advanced method of visualising data has been used by Network Rail engineers to allow for more cost-effective, safer, more reliable and preventative maintenance of the railway assets procedures.

The smart pantograph looks the same as a normal pantograph but it has fibre optic sensors inside. The sensors are not as vulnerable to extreme weather or high electrical currents because they sense the surrounding environment and transfer data using light. The pantograph provides engineers with real-time data of a train’s condition, coupled with the information extracted from GPS and a camera, allowing the engineers to schedule preventive maintenance and fix problems before they cause disruption. The engineers can pinpoint the exact location of an incoming fault.

Since 2018, Network Rail has been using smart pantographs on their high output plant system (HOPS) trains. The data the pantographs are collecting is also being used on the Great Western mainline for scheduling maintenance and repairs.

Smart pantographs come with a perk for the environment. Since they can fit on existing trains, there is no need to replace and rebuild them. As they help with scheduling preventive maintenance, the pantograph and OLE can stay in use for longer and do not end up on the scrap heap at the first sign of trouble. No materials go to waste.

Trains running in better conditions for longer is good for passengers who are in need of smooth and fast journeys, which they are more likely to enjoy thanks to smart pantographs. This makes train travel more appealing to prospective rail customers and has the potential to create another benefit for the environment: if more people swap their car journey for a train, there will be less congestion on the roads.

Being able to carry out preventive maintenance is great for engineers and rail companies too, saving them millions of pounds they would lose to unscheduled maintenance. Thanks to the integration of the smart pantograph, GPS and camera, engineers can find the precise location of where the repair needs to happen.

As a result, engineers can work in safer conditions, as they are better informed of the train operation conditions allowing for earlier actions to be taken.