Preventing bridge strikes

Being somewhat involved directly with maintaining Network Rail's infrastructure, I can vouch for the disruption this causes to the rail network and hence costs.

When an over height vehicle strikes a bridge, depending on the type of bridge all rail traffic may be stopped immediately.  Then an inspector from one of our contractors goes out to examine the bridge and either decides to re-open the line to full line speed, re-open the line to a reduced line speed or call for immediate repairs with the line remianing shut, the clock ticking and the meter running.

When working on the railway you take what is known as an Engineering possession.  This is a period where the railway is closed to trains and us Engineers then jump on and do what we need to do.  If you hand back a possession late you are hit for the delay costs.  Depending on the part of the rail network you are on you can be charged £100+ per train delay minute.  If you delay one train, you delay the 19 that are following it, not to mention the other 20 that will pass over in the other direction.  So 40 trains delayed by 30 minutes or so very quickly add up to 40x30x100 = £120,000!

The one bridge strike I was involved in was due to a lorry carrying an excavator.  He hit a steel bridge weighing around 29 tons.  The bridge was moved horizontally by 600mm and the 40mm thick by 600mm wide flange was twisted thru an angle of 45 deg.  I got the job to assess the load carrying capacity of the damaged girder, detail up a repair to it and then when the desision was made to replace it, the job of designing a new bridge.

If Network Rail does persue the offending motorists insurance company for the full costs, it would bankrupt that insurance company.  Remember Great Heck/Selby disaster in 2001?  When a guy in a landrover towing a trailer loaded with a car managed to drive for several hundered meters off the motorway before stopping on a railway line which derailed a passenger train into the oncoming path of a freight train, this wrecked the passenger train and freight train at a cost of tens of millions of pounds.  His insurance company was liable to a certain extent.

By the way it is fairly common for cars (inc BMW's) to hit bridge parapets/go through bridge parapets or approach fences and then land on the railway forcing the railway to be shut.

Andrew