Report on bridge strikes and clearances

Following the clutch of Broadway bridge strikes we had last year (none recently though) our structures engineer has prepared a useful little report on headroom and strike histories on each of our bridges along the line. He is happy to share this with our readers:

GLOUCESTERSHIRE WARWICKSHIRE RAILWAY

REVIEW OF BRIDGE HEADROOM CLEARANCES & STRIKE HISTORIES

The GWS Railway has intersections with roads and farm tracks at 46 places along the roughly 15 miles of trackbed that it owns.

Of these, 17 are Overline bridges, where the road goes over the railway and consequently these bridges cannot be subjected to impact from any road vehicle, whatever their height. This leaves 29 bridges which could be the subject of a vehicle strike.

We next have a group of 12 Underline Farm Accommodation bridges, which allow small farm vehicles, tractors and trailers and similar, to pass beneath the railway from one part of a farm to another. These bridges have widths and headrooms of the order of 3 to 3.5m.  They are never used by standard road vehicles so do not present any risk of being struck. This then leaves us with 17 bridges to assess.

There are only 2 structures on the railway that meet current minimum motorway standards of 5.03m (16’-6”) namely – 12 (Stanway Viaduct) and 21 – Pottery Bridge. This latter is a brick arch bridge which only provides the full headroom clearance across the centre 3m width. See pictures below.

Bridge 12 (Stanway Viaduct) - roadside pier under repair. The height to the arch springing point bed stone (hidden behind thick Ivy- since removed!!)  is app. 6m (19’- 9”). The semi-circular arch rises a further 5m (16’-0”) app .

As noted Bridge 21 (Pottery Bridge) provides the full standard minimum clearance, only between the two vertical white lines, visible in this picture.

The remaining 15 bridges, their headrooms, road crossing details and our knowledge of their strike histories, are detailed in the chart below. As you can see there are 6 bridges that have never been hit. You will also see that several of those hit-free ones are lower (up to 530mm lower) than Bridge 1 at Broadway. Clearly it is not just a question of height but also of the traffic likely to be using the road. As you can see virtually all of our bridges cross unclassified roads, but naturally some are busier than others and perhaps then attract more, and larger vehicles than others.

Thus our strike “problems” really only relate to 9 bridges, of which 5 have only been hit only once. 6 of the 9 that have been hit were done without our knowledge, but were spotted during the regular visual inspections that we carry out. Thus they could have occurred prior to our ownership, i.e. over 34 years ago, or at any time before that.

Thus and finally, it becomes clear that the serious bridge strike problems only lie with bridges 1 & 39, plus the recent addition of bridge 6. We think that this one is slowly becoming known to the local users, who had about 25 years without a deck to worry about!

Bridge  No.	Bridge Name	Chainage	Headroom Metric ; (Ft. & Ins)	Road beneath	Strike history	Type
1	Station Road, Broadway	4 - 76	4.4 M : 14 ’– 3”	B 4632	At least 10 known	Steel deck
2	Childswickham Road, Broadway	5 – 16	4.8 M : 15’ – 9”	Unclassified	2 minor	Steel deck
3	Pry Lane	5 – 34	3.4 M : 11’ – 3”	U/C & Cul-de-sac	1 extremely minor	Brick arch
5	Little Buckland	6 – 26	4.1 M : 13’ - 6”	Unclassified	None	Steel deck
6	Laverton Halt  (Opened 12. 2009)	6 – 79	4.0 M : 13’ – 3”	Unclassified	At least 4 since 2009	Concrete deck
15	Didbrook 1	10 – 03	4.5 M : 14’ – 6”	Unclassified	None	Brick arch
16	Didbrook 2	10 – 14	4.2 M : 13’ – 9”	Unclassified	None	Concrete deck
26	Gretton Village	13 – 33	4.5 M : 14’ – 9”	Unclassified	1 medium	Steel deck
28	Stanley Pontlarge	13 – 67	3.7 M : 12’ -  6”	U/C & Cul-de-sac	None	Steel deck
31	J. J. Farms, Far Stanley	14 – 28	3.6 M : 12’ – 0”	U/C & Cul-de-sac	1 minor	Steel deck
32	Prescott Road	14 – 40	4.3 M : 14’ – 0”	Unclassified	1 minor / medium	Steel deck
34	Gotherington Skew	15 – 17	4.3 M : 14’ – 0”	Unclassified	1 minor	Steel deck
35	Granna Lane	15 – 25	3.7 M : 12’ – 6”	U/C & Cul-de-sac	None	Conc. Filled trough
36	Manor Lane	15 – 71	3.8 M : 12’ – 9”	U/C & Cul-de-sac	None	Brick Arch
39	Station Road, Bishops Cleeve	16 – 71	4.0 M : 13’ – 3”	Unclassified	At least 4 known	Steel deck

It is a fact of life that any vehicle which does strike a bridge, unless it is jammed tightly, will try to get away before anybody sees it, as the consequences of prosecution and recovery of damage repair costs, insurance excess, etc. could be very substantial. 

Mostly, the only way that we know that a strike has occurred is because of the debris left behind, in the road, see photo - left.

Bridge 1, is over a long straight section of the very busy, former A46 road from Broadway to Evesham, and consequently is a very attractive road to lorries. Despite being a fairly high one, this bridge has been subject to many strikes over most of its life. It is likely that there has been a decrease in frequency since the Broadway by-pass was opened, in 1998, but several strikes have occurred since.

After the trains stopped running in 1976, because none of the strikes was serious enough to warrant an immediate repair, no attempt has been made to do so, either by Network Rail (British Rail), before 1981, or GWSR, since. Consequently, since the 3 really bad strikes had happened, it has become almost impossible to identify subsequent minor grazes, as vehicles tend to strike roughly the same part of the bridge each time. The total number of strikes, on this bridge, could therefore be far more that stated.

Following the recent repairs and upgrading and painting works, of this bridge, completed in September 2014, there have been at least 4 strikes within a period of 3 weeks.  Almost certainly this was partly down to the introduction of a road diversion scheme which, we believe, directed some over-height traffic under this bridge. Complaints to Worcs C.C. Highways dept. led to the diversion being changed and the repeated strike situation seems to have stopped.

Bridge 6 stood, until 2009, without any deck at all for over 25 years and this may have led to a spate of strikes in the first 3 or 4 years, after the new deck was constructed. 

Laverton and its new deck being built

We are fairly certain that the damage is being caused by a locally owned hydraulic tele-handler. Again repeated strikes, in roughly the same position, make it difficult to tell if further strikes have occurred or not. We suspect that there hasn’t been a strike for a year or more and so we may be able to get a concrete repair done and will then know for certain. Maybe the driver has finally realised that it is causing his 8 T. machine far more damage than our 125 tonne bridge deck!!

Since I became the Bridges Engineer in 2005 there have been just 2 cases where, either the vehicle has become wedged, or the damage to the vehicle meant that it stayed at site long enough for there to be witnesses to get details of the vehicle, to support a claim.  In a 3^rd case we were also able to make a claim. The bridges were :-

1.       No. 1 (Station Road, Broadway) – payment received from our insurers, but recovery of our excess is not clear. Repairs done in 2014.

2.       No. 26 (Gretton Village) – payment from our insurers and recovery of our excess. Repairs done in 2009.

3.       No. 39 (Station Road, Bishops Cleeve) – payment received from our insurers in 2008. Excess not recovered. Repairs still outstanding.

This last Bridge No.39 – Station Road, Bishops Cleeve - was struck in March 2007. It is in a large and expanding residential area with several businesses close to the bridge and a large school, not far away, with most children being drawn from the area around the bridge. Thus the need for a complete closure will inevitably cause huge disruption to many people and businesses, although provision for pedestrians, through the works, will be provided.  The bridge only has an alternately worked one way priority traffic system (see photo left) so traffic light controlled, one way working is not possible.

SUMMARY OF BRIDGE STRIKE PROBLEMS

Hopefully, from the data above, it is clear that our main problem only lies with bridge 1. Our Civil Engineering Director is looking into the various options available to introduce extra warning signs, or barriers (costs are huge!). Hopefully our relationship with Worcestershire County Council, during the B2B contract may lead to more of a shared responsibility in mitigating future strikes.

17^th January 2015