Security cameras that can detect movement are being used in a hi-tech effort to prevent graffiti attacks on the railways.
Graffiti costs Central Trains an estimated £300,000 a year
Central Trains says it is the first UK rail company to introduce the motion-sensitive cameras at stations.
The "FlashCam" takes a photograph of the culprit and issues an audible warning that the police are on their way.
Central Trains says graffiti costs the company about £300,000 each year to clean up.
A spokesman for the company said such attacks frequently caused trains to be cancelled, especially if the offending words were racist and needed to be removed immediately.
The train operator says it copes with an average of about one incident each week, with the worst hotspots being in Royal Leamington Spa, Nottingham, Boston and Worcester.
FlashCams were placed at train sidings in Worcester and Leamington last week.
The firm said it intends to invest in up to 30 more of the devices at notorious graffiti spots across its network, which extends across the Midlands up to the North West and down to south Wales.
If the technology detects any movements it will sound the warning: "Stop. You are in a secured area. Leave now - the British Transport Police have been contacted and are on their way."
Central Trains said the equipment, which was first used in the United States, costs £1,300 per unit.
Peter Cushing, operations director for Central Trains, said: "Graffiti has been an ongoing problem for a long time and now we are determined to stamp it out once and for all.
"The camera has a motion sensor built into it, a flash 35mm camera and a loudspeaker.
"It's not deafening - but it's enough to put anyone off who wants to do graffiti there."
Central Trains spokesman Ged Burgess added: "(The FlashCam) has been very successful in reducing graffiti in the railway yards in the US, which is a far bigger problem there than it is here.
"Nevertheless, we are hoping that it will result in a reduction in the inconvenience that passengers have when their trains are not in service because we are having to clean graffiti off the windows.
"We also hope it will improve safety because, at the end of the day, graffiti artists are putting their lives at risk by trespassing on the sidings."
"The added bonus for us is that these can be installed for £1,300 per unit - a fraction of the cost of CCTV systems - which can be up to £30,000 each."
Police are already studying the first rolls of film in the hope of identifying those responsible for the latest acts of vandalism.