Special paint helps NR find bridge electrification solution
Network Rail is claiming a world first, with a project involving electric-resistant paint combined with voltage-controlled clearance in Cardiff.
It says this combination has saved around £40 million by enabling a Victorian railway bridge to be used by electric trains, avoiding the need for railway closures and delays.
Intersection Bridge, located east of Cardiff Central and which carries the Valley Lines over the line to Newport, was too low to safely fit all the equipment required for electrification.
NR Engineering Expert Richard Stainton explained: “Ordinarily, this would force us to demolish it and rebuild it at a greater height, to keep electric trains a safe distance away from the bridge as they pass under and to stop them from electrifying the bridge itself or anything on it.”
The paint features a specialist coating developed with the University of Southampton.
It is used alongside lineside equipment including surge arresters and insulated bridge arms to insulate the structure from electricity.
NR said that for the first time anywhere in the world,
the electric-resistant paint was combined with voltage-controlled clearance, which allowed the electrical clearance gap to be reduced by 20mm from the OLE to the bridge and 70mm from the OLE to the train roof.
Peter Smith-Jaynes, NR Regional Asset Manager, Electrification, Wales & Western, said: “It’s a very busy rail-over-rail bridge, with a canal underneath that, and it’s surrounded by high-rise buildings. Just accessing the bridge would have been difficult… but knocking it down and rebuilding it would have been nearly impossible. We had to find another solution.”
Stainton added that typically, a third of electrification project costs go on reconstruction and modifying civils structures including tunnels, bridges and stations.