Cross purpose

Obstacle detection technology designed to prevent collisions at level crossings will soon be used on the UK railway network.


Obstacle detection technology designed to prevent collisions at level crossings will soon be used on the UK railway network, the government body responsible for rail safety has confirmed.


The Rail Safety & Standards Board (RSSB) will later this year invite bids for a contract to develop a system that can identify dangerous obstacles and bring trains to a halt.


The announcement follows publication of the RSSB’s report into last year’s Ufton rail accident, in which seven people died when a train collided with a car parked on a half-barrier crossing in Berkshire.


Some rail technology experts are urging the UK to adopt a similar approach to Japan, which is said to have cut accidents on level crossings by half since installing advanced systems on its network.


Michael Woods, head of operations at RSSB, said that various technologies will be under the spotlight. ‘We’ll be looking at everything from infrared to motion detectors and radar, as well as less likely options such as pressure sensors.’ Woods added that vision-based systems would probably be favoured because of their ability to distinguish between different types of obstacles.


One of the keys to a successful system will be getting it to respond only to obstacles that are likely to cause the train to derail, avoiding constant shutdowns to services. It will also have to demonstrate a reliable method for alerting approaching trains. Woods said that while this could take the form of a radio warning to drivers, he also expects to be looking at technology that can send a signal directly to the brakes.


One of the groups bidding for the RSSB contract is headed by Dr Clive Roberts of Birmingham University’s school of electronic and electrical engineering. While reluctant to discuss details of his proposed system, Roberts agreed that a vision-based approach is likely to provide the best solution. Roberts also claimed that there are a number of overseas obstacle detection projects that could provide the UK with inspiration. He singled out Japan, where the introduction of ultrasonic, radar and stereo-camera technologies is thought to have cut level crossing accidents by around 50 per cent.


Prof Rod Smith, head of mechanical engineering at Imperial College, agreed that the answer for the UK lies overseas. ‘There’s technology in other countries that works perfectly well. They’ve spent years developing it, ironed out all the problems, so why can’t we bite the bullet and import it?’


The Japanese approach, however, is apparently not without its problems. RSSB’s Woods claimed the system is bedevilled by a high level of false trippings that frequently cause queues of road traffic. He said that while this is just about tolerated in Japan’s more compliant society, the temptation to zigzag round the barriers could prove too much for UK motorists.


Meanwhile, UK train drivers’ union ASLEF has weighed in with a suggestion of its own. Its general secretary Keith Norman claimed that a system developed by South Wales-based Global Laser Technology Solutions could do the job. In use in Hong Kong, Trackmaster is a laser-based detection system that relays information to monitors in the driver’s cab.


Woods appeared unconvinced, however. ‘TV screens detract from a driver’s ability to do what he or she is paid to do, which is to observe and obey signals — we’re suspicious of any system that complicates a driver’s task.’


For Imperial’s Smith the real problem is the result of an inherited Victorian infrastructure that the UK has never improved — the ultimate solution should be more drastic, he said. ‘If you were building a highspeed rail link you wouldn’t have it anywhere near a road. In the long run there is no better way than separating trains from road traffic.’