Bridge strikes: prevention, and what to do after one

A bridge strike is one of the few incidents in transport that is simultaneously uncommon, very costly, disruptive far beyond the operator, and almost always avoidable. The costs land on the railway or highway authority as much as on the operator, and the regulatory attention that follows is significant.

The driver usually did not know the height

Investigations repeatedly find the same root cause: the driver did not know the actual travelling height of the vehicle they were in. Not carelessness — a tractor unit coupled to an unfamiliar trailer, a vehicle with equipment fitted since the last check, or a height marked in the cab that refers to a different configuration.

Which makes the primary control knowing and communicating the height for this combination today, not reminding drivers to be careful. A cab height indicator that is wrong is worse than none, because it is trusted.

Route planning is the other half

Satellite navigation designed for cars does not know a vehicle's height, and drivers under time pressure follow it. Where an operator has not provided routing appropriate to the vehicle, the practical default is whatever the driver's device says — and that device has no idea what is being driven.

In practice: the trailer swap nobody re-measured

A driver swaps to a different trailer mid-shift at a partner's yard. The height card in the cab refers to the trailer they started with. The route is familiar and has a low bridge on it that the original combination cleared.

Everything about that is ordinary. The missing control was a step requiring the travelling height to be re-established at the point of coupling, which is the moment it changes.

Common mistakes

• –Height indicators that refer to a previous configuration
• –No step to re-establish height at coupling or after equipment changes
• –Relying on general-purpose satellite navigation for routing
• –Treating it as a driver-attention problem rather than an information problem
• –No reporting culture for near misses, which are the free warnings
• –No agreed procedure for what a driver does immediately after a strike

What to do immediately after one

The driver's priorities are fixed and worth rehearsing in advance, because nobody works them out well under the circumstances: make the scene safe, and report it to the infrastructure owner without delay — a struck rail bridge may need trains stopped, and that decision belongs to the railway rather than to a judgement about whether the damage looks serious.

The operator's part is a procedure the driver actually knows, including who they call first and what information will be asked for. A driver deciding at the roadside whether a strike is worth reporting is being asked the wrong question.

Getting this right

Near misses are the free information here — a driver who had to reverse out of a route, or who noticed clearance was tighter than expected, is telling you about a routing problem before it becomes an incident. That only surfaces where there is a route to report it and no penalty for doing so, which is the same culture question behind end-of-shift debriefs.

• –Re-establish travelling height at coupling and after any equipment change
• –Provide routing appropriate to the vehicle rather than leaving it to a driver's device
• –Rehearse the immediate response, including who to call first
• –Report to the infrastructure owner without assessing damage yourself
• –Capture near misses and treat them as routing information

One practical test: ask a driver the height

Walk into the yard and ask a driver the travelling height of the vehicle they are about to take out. Then check it against the combination they are actually driving today.

Where the answer comes from a cab sticker that refers to a previous trailer, or from memory of a different unit, you have found the root cause before it finds you. The control is knowing and communicating the height for this combination today — and the moment it changes is coupling, which is where the check belongs.

• –Re-establish travelling height at coupling and after equipment changes
• –Provide routing appropriate to the vehicle, not a driver's own device
• –Treat a wrong height indicator as worse than none
• –Rehearse the immediate response, including who to call first
• –Capture near misses and treat them as routing information