Limpley Stoke Bridge Strike (Monday 23/03/2026)

[The exile]

Does the height signage get reviewed after the road is resurfaced?

Even if it is, the rounding means the signage might still be “correct”. A semi- regular who “knows” they have a bit of leeway suddenly finds they haven’t!

 

[edwin_m]

Someone who's decided that particular bridge is high enough probably wouldn't be checking whether the signage has changed anyway.

 

[Dave61]

Does the height signage get reviewed after the road is resurfaced?

Considering that the lorry driver is ignoring the flashing warnings, I somehow doubt thet take any notice of the height sineage. After all it worked last time !

Besides what are the chances of that stretch of road being resurfaced? If not a tar and chippings bodge job then they usually scrape the old one off anyway.

 

[stuving]

I'm sure it will be helpful for this discussion to have the relevant bit of "Traffic Signs Manual Chapter 4" (2018) to hand. There is a lot more detail, of course, and pictures of signs, but this deals with measurement and clearances:

7.3.3. All bridges and other structures with a headroom of less than 16’‑6” (5.03 m) should be
clearly signed. The Regulations require heights on new signs to be shown in both imperial and
metric units. Imperial and metric heights should be calculated separately (see 7.4 & 7.5).
7.3.4. The bridge height should be re‑measured when works on the road or to the bridge
might have affected the available headroom. [...]
7.3.5. Care should be taken to ensure that vehicles of the maximum length permitted by
the Construction and Use Regulations will be able to pass safely under the bridge. This is
particularly important where the road dips or hogs sharply or is on a curving alignment under
the bridge. Changes in gradient might affect the headroom, e.g. the effective clearance will
be reduced for a long wheel base vehicle spanning a dip. Where the road passing under a
structure is on a sag curve, the headroom should be measured along the carriageway over a
25 m chord.

7.4 Imperial height
7.4.1. The imperial figure shown on signs to indicate the available headroom should be at least
3 inches less than the measured height to allow a safety margin. If the resulting figure is not a
multiple of 3 inches, it should be rounded down to the nearest lower multiple of 3 inches.
Example 1: measured height 15’‑2”:
Step 1 subtract 3” to create a safety margin 14’‑11”
Step 2 round down to nearest multiple of 3”
Step 3 sign as 14’‑9”.
Example 2: measured height 14’‑6”:
Step 1 subtract 3” to create a safety margin 14’‑3”
Step 2 sign as 14’‑3” (rounding down not required as already a multiple of 3”)
Thus, the maximum headroom that will normally appear on a sign is 16’‑0”.

7.5 Metric height
7.5.1. To obtain the metric figure shown on signs, the bridge height should be measured to two
decimal places, rounding down to the nearest 0.01 m. The following method is then used to
calculate the appropriate signed height:
a) if the second decimal digit is 8 or 9, delete it and sign the bridge with the remaining whole
number and the first decimal digit;
b) Example 1: measured height 4.19 m:
c) Step 1 remove the final 9 (subtract 0.09 m)
d) Step 2 sign as 4.1 m
e) if the second decimal digit is 7 or less, delete it and reduce the first decimal digit by 1. Sign
the bridge with the remaining whole number and first decimal digit, as reduced;
f) Example 2: measured height 4.17 m
g) Step 1 remove the final 7 (subtract 0.07 m)
h) Step 2 reduce first decimal digit by 1 (subtract 0.1 m)
i) Step 3 sign as 4.0 m
7.5.2. The height shown on the sign must be to only one decimal place. The maximum
headroom that will normally appear on a sign is 4.9 m

A couple of points raised by that -

• How, before we had surveyors' "total stations", did you measure a bridge height simply over a 25 m chord along the road?
• It looks as if the bridge height includes the clearances, so the vehicle marked height can be exact. But which is required to allow for dynamic gauging, such as suspension bounce or body sway?

It says the metric and imperial measurements are to be calculated separately, not measured separately. I take that to mean a single accurate measurement (most likely to be metric) can be converted, before the rounding, adding clearances, etc. But in the Limpley Stoke case it does look like the marked imperial height was converted to metric and then processed again, giving double rounding on the bridge itself. It's tempting to say the advance sign was done off the office record which had the raw measurement in it, which avoided that issue. But I suspect that's too neat to be true.

 

[Ashley Hill]

It appears this bridge was struck again this afternoon about 1700. Location of bridge given as Winsley Hill bridge on the B3108.

 

[edwin_m]

It appears this bridge was struck again this afternoon about 1700. Location of bridge given as Winsley Hill bridge on the B3108.

Glad I missed that one - I would have passed over about 1400.

Someone on NR should really be badgering about that warning signage, or the lack of. I wonder if the problems have to do with the multiple highway authorities involved - the A36 is National Highways, the B3108 is Bath and North East Somerset responsibility where it meets the A36 but goes into Wiltshire before it reaches Limpley Stoke.

 

[The exile]

Third time in a fortnight! No idea if it’s the same bridge, though whoever was issuing the special stop orders at Bath said he thought it was.

 

[Snow1964]

Glad I missed that one - I would have passed over about 1400.

Someone on NR should really be badgering about that warning signage, or the lack of. I wonder if the problems have to do with the multiple highway authorities involved - the A36 is National Highways, the B3108 is Bath and North East Somerset responsibility where it meets the A36 but goes into Wiltshire before it reaches Limpley Stoke.

Network Rail could easily cut down the vegetation they have allowed to grow on the trackbed of the third track (former Camerton branch) which is immediately alongside the road on approach and erect warning signs facing the road on their own land.

If road authorities (eventually) add signs, extra warnings signs are better than no advance warning signs (actually there is a sign with some text on a blue sign below other signs, but virtually impossible to read it and take in all other info on same pole, but as an advance warning it is almost useless.)

Have checked and appears there is a 3 day line block closure during first weekend in May, perhaps they could arrange to cut the vegetation and get some sign poles installed facing the road on their land during the approx 80 hours line is closed. Network Rail need to be more proactive as this bridge is hit from A36 direction far too regularly

 

[Snow1964]

And the bridge has been hit again today causing more train cancellations

Why are Network Rail doing nothing to improve the signage, and cut the vegetation (extending from their land) that blocks visibility of height signs on the approach

 

[mcmad]

Because the responsibility for signage lies with the roads authority.

 

[MartinC]

And the bridge has been hit again today causing more train cancellations

Why are Network Rail doing nothing to improve the signage, and cut the vegetation (extending from their land) that blocks visibility of height signs on the approach

Network rail have vegetation failings. Slightly off OP's topic but there is a weak bridge over Bournemouth main line in the New Forest. The warning sign is hidden by vegetation. I pointed this out to the NR employee who was fence checking six months ago. Still obstructed!

 

[Annetts key]

Network Rail have in the past reduced funding for the maintenance organisation. Within this, the part that is responsible for vegetation management is called Off-Track.

As the maintenance budget is still under a lot of pressure, I really don't see any change in their priorities in the way that they manage vegetation.

Because the Off-Track now has low numbers of employees, any large vegetation clearing means Network Rail has to hire in a contractor to do the work.

I can't provide any link or source because my information is from internal Network Rail meetings.

 

[voyagerdude220]

Third time in a fortnight! No idea if it’s the same bridge, though whoever was issuing the special stop orders at Bath said he thought it was.

Out of curiosity I've just had a quick look on Google Maps and can't see any other Bridges which could have been involved.

 

[Strathclyder]

Network Rail have in the past reduced funding for the maintenance organisation. Within this, the part that is responsible for vegetation management is called Off-Track.

As the maintenance budget is still under a lot of pressure, I really don't see any change in their priorities in the way that they manage vegetation.

Because the Off-Track now has low numbers of employees, any large vegetation clearing means Network Rail has to hire in a contractor to do the work.

I can't provide any link or source because my information is from internal Network Rail meetings.

None of that is surprising - but no less 'head meets desk' frustrating - considering the frankly shambolic state of lineside vegetation up and down the network and all the issues/costs that come with letting it turn into a mini-jungle. Would neatly explain why some linesides go at least 10 years between trimmings, never mind full-scale clearences (those you're lucky to see happen every 15 years). Obviously cheaper to let the passing trains mold the overhanging foliage to their shape than to outright remove the damn stuff altogether.

A pitiful state of affairs, one as you say won't be changing for the better anytime soon.

 

[voyagerdude220]

Looking at this particular bridge at the bottom of Winsley Hill on Google Maps, yes there are some warning signs about the low height of the Bridge and the narrow width of the Road, but I suspect a big cause of the accidents with large vehicles colliding with the bridge being because there aren't many (if at all any) places wide enough between where the warning signs have been placed and the Bridge itself for wide lorries etc. to be able to make a u turn safely because the roads are so narrow in the area.

 

[Snow1964]

Looking at this particular bridge at the bottom of Winsley Hill on Google Maps, yes there are some warning signs about the low height of the Bridge and the narrow width of the Road, but I suspect a big cause of the accidents with large vehicles colliding with the bridge being because there aren't many (if at all any) places wide enough between where the warning signs have been placed and the Bridge itself for wide lorries etc. to be able to make a u turn safely because the roads are so narrow in the area.

The problem has never been from Winsley Hill side (there are warning signs just before roundabout at other end of Winsley village), advising overheight vehicles to turn around

The problem is northbound traffic turning off A36 trunk Road, heading for A46 (which leads to M4 and M5 north).
As traffic approaches on Limpley Stoke (road) viaduct they are faced with signs which have following warnings :
straight ahead (on A36) 18t limit ahead in Bath
left (to Combe Down) 7.5t limit
right (B3108 to Bradford on Avon), no restrictions even though this has low rail bridge.

The 18t limit on Cleveland bridge in Bath is relatively recent, but there are massive yellow signs on Warminster bypass (just before where A36 and A350 diverge) warning of the weight limit, but nothing warning about height limit.

== Doublepost prevention - post automatically merged: 9 May 2026 ==

As the maintenance budget is still under a lot of pressure, I really don't see any change in their priorities in the way that they manage vegetation.

That might be true generally across the Network.

But the massive cost of sending someone to inspect Limpley Stoke bridge every few weeks, plus cost of disruption to train Operators for disruption must be lot more than sending a couple of people with long reach hedge trimmers to make the obscured warning signs visible as traffic approaches.

Suggests no one in Network Rail management can spot the current waste of money and potential cheap solution.

 

[Annetts key]

But the massive cost of sending someone to inspect Limpley Stoke bridge every few weeks, plus cost of disruption to train Operators for disruption must be lot more than sending a couple of people with long reach hedge trimmers to make the obscured warning signs visible as traffic approaches.

Suggests no one in Network Rail management can spot the current waste of money and potential cheap solution.

Nothing to stop you from making a call to the Network Rail helpline to report which signs are obscured. Or if you work for the railway, getting it reported to Network Rail fault control at Swindon.

At least the problem then gets logged on Network Rail's system.

 

[voyagerdude220]

Not again(!)....

Copied from GWR's Journey Check website:

Due to urgent repairs to a bridge between Bath Spa and Westbury all lines are closed.
Train services running through these stations may be cancelled or diverted via Melksham. All stations between Bath Spa and Trowbridge will not be served. Disruption is expected until the end of the day.
Customer Advice
-
What has happened?
-
We've been informed that a vehicle has struck a bridge in the Freshford area. The bridge will have to be examined to make sure its safe and any debris cleared.

 

[chipbury]

A quote from national rail

"This service has been cancelled because of a road vehicle colliding with a bridge earlier today"

Apparently Limpley Stoke bridge was hit sometime this morning and was closed to rail traffic for a few hours whilst an inspection took place.

 

[mr_moo]

UK road signs are weird and the two different heights are quite variable. Here's the great Matt Parker with a video explaining it all:

 

[Ashley Hill]

Struck again this evening.

 

[The exile]

And again today (at least I guess it’s the same bridge). Surely it’s time to get cameras up (preferably as part of some kind of preventative measure - but at least so the culprits can be identified and made to cough up).

 

[voyagerdude220]

And again today (at least I guess it’s the same bridge). Surely it’s time to get cameras up (preferably as part of some kind of preventative measure - but at least so the culprits can be identified and made to cough up).

I suspect it will indeed be the Limpley Stoke Bridge [on Winsley Hill] involved, as there aren't many other bridges around there.

 

[chipbury]

It was the same bridge as I saw the Network Rail team there at midday.

 

[Incogcyclist79]

And another bridge strike in the Freshford area. I'm assuming it's the same one at Limpley Stoke again. Hope it's resolved by the time I need to get back through there this evening!

Incident: Freshford | National Rail

Lines reopened: disruption between Bath Spa and Westbury . Find details of all current incidents on National Rail Enquiries.

www.nationalrail.co.uk

A road vehicle has collided with a bridge in the Freshford area. As a result, the line is blocked. Trains running between Bath Spa and Westbury may be cancelled or revised.

Disruption is expected until 17:45.

 

[The exile]

It’s about time cameras were fitted and punitive fines introduced.

 

[Snow1964]

And another bridge strike in the Freshford area. I'm assuming it's the same one at Limpley Stoke again. Hope it's resolved by the time I need to get back through there this evening!

Incident: Freshford | National Rail

Lines reopened: disruption between Bath Spa and Westbury . Find details of all current incidents on National Rail Enquiries.

www.nationalrail.co.uk

The road only reopened at the weekend, after being shut 2-3 weeks because of an emergency gas main repair by the canal bridge that needed special parts manufactured

 

[IrishDave]

It says the metric and imperial measurements are to be calculated separately, not measured separately. I take that to mean a single accurate measurement (most likely to be metric) can be converted, before the rounding, adding clearances, etc. But in the Limpley Stoke case it does look like the marked imperial height was converted to metric and then processed again, giving double rounding on the bridge itself. It's tempting to say the advance sign was done off the office record which had the raw measurement in it, which avoided that issue. But I suspect that's too neat to be true.

So, my reading of the rules is that anything between 4.180m and 4.279m high would be signed as 4.1m, and anything between 14'0" (4.268m) and 14'3" (4.343m) would be signed as 13'9". So a bridge between 4.268m and 4.279m high would be correctly signed as 4.1m / 13'9".

This accords with the view of the "Height Hunt" website, which tries to find every possible combination of bridge height sign, and explains it all in the process:

Height hunt

Height hunt

 

[The exile]

The road only reopened at the weekend, after being shut 2-3 weeks because of an emergency gas main repair by the canal bridge that needed special parts manufactured

That explains why there haven’t been any bridge strikes in the last 2 - 3 weeks!

 

[Ashley Hill]

And another bridge strike in the Freshford area. I'm assuming it's the same one at Limpley Stoke again

It is.