Anyone who regularly commutes to work by train will be aware of the huge demand on rail services. According to Network Rail, parts of the UK railway are already operating close to capacity, but demand for passenger and freight services continues to increase.
Seeking a cost-effective solution, Alstom is turning to laser-scanning technology to ensure that existing rolling stock and rail infrastructure can be as reliable, safe and well maintained as possible to withstand the stresses that come with increased usage.
Alstom has recently completed a pilot trial of its TrainScanner device on the Class 390 Pendolino tilting trains operated by Virgin Trains in Manchester, and plans to introduce a second machine at Oxley depot near Wolverhampton in the West Midlands.
The TrainScanner uses 3D laser-scanning technology and cameras with smart prognostics software to build up a highly accurate picture of the health of the train as well as enabling predictive maintenance for wheels, brake pads and the overhead pantograph carbon strips.
Maximising use
Rob Whyte, managing director of Alstom’s regional and intercity business in the UK, says: “With the growth in the rail market, companies such as Northern Rail and TransPennine Express are buying hundreds of new vehicles which they have to fit into the existing network somehow. That either means lots of new depots everywhere, which in congested areas like cities is pretty hard – or we’re going to have to maximise the use we get out of the current facilities. That’s really where we’re focusing our attention on.”
The successful testing of the TrainScanner in Manchester provided “phenomenally accurate” data, which Whyte says surprised those who had been more sceptical of the technology.
High-resolution lasers on the scanner measure brake pads, wheel diameters and pantographs down to around 0.5mm resolution, allowing Alstom to visualise tiny chips and prolonged wear that wouldn’t be picked up by the human eye.
The laser scanners also undertake a confidence check, looking at fixed points on the train to check levers and latches are in the correct positions. Cameras also provide a physical image for operators.
While the data has already produced nearly 100% accuracy levels, the TrainScanner carries out its own confidence check of the data and provides an alert if it’s unable to scan part of the train. If it’s unable to provide a reading, workers decide whether the train needs to be re-scanned, taken for a human inspection or sent back into operation.
Whyte says: “We have run it at 97% reliability of measurements. That means that only 3% of the time it’s saying it couldn’t measure a part properly, therefore it won’t read it. So we are 100% confident with its ability to read, but, so far, it has a 97% reliability in the reading.”
The scanning is convenient as it takes place at night when the train goes through a wash plant at a depot, travelling at 5mph. Each vehicle is identified by an RFID tag on its axle as it travels through the scanner.
Whyte believes the technology is superior to manual inspection carried out by a staff member walking underneath the train at night wearing a head torch. He says: “These machines have picked up small things like a missing brake pad from a brake disc. While there’s no safety issue related to that, pistons or calliper scoring onto the disc without a pad could have resulted in a wheel set being taken out early, which is a disruption to the operators and a cost to us as the maintainer.”
Whyte believes that the technology’s greatest strength lies in its prognostic capabilities. Over the past 18 months of the pilot trial, Alstom has been able to identify which routes cause trains the greatest wear. The firm can then determine whether it’s the train that’s the problem or the existing infrastructure, explains Whyte.
This, combined with static information from on-board diagnostic systems on Pendolinos that monitor things like power feeds, provides an accurate picture of what’s happening.
So far, Alstom has been able to see 25% of the Pendolino fleet every night, monitoring things like brake pad thickness and wheel wear more closely than ever before. This means they’re able to increase the time needed before replacements are required, while still working within safety margins.
Bespoke software
The data is presented to a team of engineers using bespoke software based on a simple traffic-light system. Users can access each train’s service history, including the latest scanning data, miles travelled and location. It also enables users to examine the thickness of a brake pad as a 3D-scanned image or from a photograph taken during the scan.
The system will even assist with planning vehicle maintenance and will automatically alert the planning team to a maintenance issue early on. Whyte adds: “It will also order the components and ensure we’re getting the right things ordered at the right time to minimise downtime.”
By adding a second TrainScanner at Oxley, Alstom will soon be capturing data for 50% of the Pendolino fleet per night. “By doubling data we will really start pushing out on maintenance which will not only improve availability and reliability, but the efficiency of the whole train system,” says Whyte.
The second ‘productionised’ prototype has had a number of design changes made to it. These include making maintenance access easier, setting the requirements in the lab rather than on site, and setting the scanner into sleepers to make it quicker and cheaper to install. It’s also bi-directional for increased scanning flexibility.
Alstom has received interest in the technology from internal projects and has also made bids with the TrainScanner included. Interest has also been expressed from operators and Alstom is now working on a commercial solution.
“The reality is that the TrainScanner is picking up things that people have missed – it’s completely reliable in its information and a doddle to use for the fleet operators, who are getting more and more valuable data out of it to use in real time rather than having to trawl through mounds of paperwork. As a result, people are 100% behind it.”
SNCF rail adopts UK track tech
A mobile laser-scanning system from Nottingham company 3D Laser Mapping has been adopted by French national railway company SNCF to improve safety and inform track upgrade works. The rail-mounted StreetMapper can survey hundreds of kilometres of track to build a detailed 3D topographic map of the track and its surroundings. This provides length data and cross profiles as well as detecting potentially dangerous objects near the track.
Dr Graham Hunter, executive chairman at 3D Laser Mapping, says: “A 2D time-of-flight laser scanner, with a 360° field of view, is used to accurately measure the distance of millions of points per second. Simultaneously, a highly accurate navigation system measures the precise geographical position and orientation of the system 512 times each second.
“These two datasets are then combined – doing so produces a high-density georeferenced point cloud.”
StreetMapper is also used by US survey company Terrametrix and technology provider AAM for rail survey projects in Australia and Southern Africa.