Interactive signs have been installed at two Worcestershire railway bridges to prevent motorists from hitting them and causing thousands of pounds worth of damage.

The signs were put up outside the Vigo and Navigation bridges near Bromsgrove as part of a Network Rail and Worcestershire County Council initiative.

It aims to benefit passengers travelling between Birmingham, Worcestershire and the West Country, following an increase in the number of 'bridge strikes' at the two locations.

In the last three years, similar incidents at the bridges have led to 8,745 train delay minutes (just over six days). This has led to the railway industry facing costs of £102,928.

The most recent strike happened at the Vigo bridge on May 1, 2007. This delayed 19 trains by 210 minutes (three-and-a-half hours) and cost the railway industry more than £3,000.

According to Network Rail, the consequences of a bridge strike can vary from minor paint scrapes to major structural damage to the bridge or the track being moved sideways by the impact.

In some cases, there have even been reports of vehicles getting stuck under the bridge.

This can cause major delays for motorists who are unable to find an alternative route or who get stuck in the resulting tailbacks, while engineers examine the bridges for damage.

John Gill, Network Rail's area general manager, said the money used to repair the bridges or lost through the resulting delays, could be used to improve rail services instead.

"Each time these bridges are hit, we have to close the railway until an engineer can examine the structure for any damage," he said.

"This not only causes significant disruption for passengers, but costs the railway industry thousands of pounds every year - money that would otherwise be used to improve services." The interactive signs work through the use of vehicle-activated technology.

This technology will warn drivers approaching the bridges from both sides if their vehicles are too tall to pass under the bridge and are likely to strike the bridge.

At Navigation Bridge - south of Bromsgrove and spanning the B4091 between Stoke Prior and Hanbury, and with a maximum permitted height for vehicles of 12ft 9in (3.8m) the signs were funded by Network Rail.

At Vigo Bridge - north of Bromsgrove and spanning the B4096 between Burcot and Red-ditch, the signs were jointly funded by Network Rail and Worcestershire County Council. The maximum permitted height for vehicles is 11ft 9in (3.5m).

Coun Derek Prodger, (Con Worcester -Bedwardine) Worcestershire County Council's cabinet member for environment, welcomed the introduction of the signs and said they should be used along other routes in the region.

He said: "These signs are important in addressing the hazard posed by high vehicles hitting railway bridges. "