Bridge strike at Plymouth (30/08)

[zwk500]

Can't say I've seen any here, particularly on the usual ones struck, but that's reassuring to hear. I'd have thought this would be worthy of further roll out.
Is there a criteria for fitting, as in three strikes and you're out we'll put up a beam?

here is one: https://www.google.com/maps/@51.992...4!1si4ezWUcSch5NXRYla0rxTg!2e0!7i13312!8i6656 on the Hitchin-Cambridge line.

It can't be done everywhere, as you've got to have a sufficiently strong structure that something clanging the beam won't get the bridge at the same time, and I'm not aware of any on arches (although there's probably some). The criteria for fitting are a combination of frequency of being bashed, strength of the bridge, and potential disruption to rail traffic, but I don't know how individual decisions are made.

 

[swt_passenger]

here is one: https://www.google.com/maps/@51.992...4!1si4ezWUcSch5NXRYla0rxTg!2e0!7i13312!8i6656 on the Hitchin-Cambridge line.

It can't be done everywhere, as you've got to have a sufficiently strong structure that something clanging the beam won't get the bridge at the same time, and I'm not aware of any on arches (although there's probably some). The criteria for fitting are a combination of frequency of being bashed, strength of the bridge, and potential disruption to rail traffic, but I don't know how individual decisions are made.

There’s some info on the pros and cons of collision protection beams in appendix B2 of one of the DfT guides:

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/350114/network-rail-bridge-strike-protocol.pdf

B.2 collision protection beams (CPBs)
B.2.1 collision protection beams are installations designed to absorb the force from an impacting vehicle and so protect the structure of a bridge. As such they are generally built into the existing bridge abutments because the Highways Act 198018 does not permit free standing supports over the highway as they would create an additional and avoidable hazard to traffic.
B.2.2 whilst cPBs may be installed under the terms of the Act
or other legal agreement covering the original bridge construction, approval from the Highway Authority is also required to protect the interests of the Highway Authority and users of the public highway. this should cover issues of headroom, signing and maintenance access and also the role of the joint signatory in the formal structural technical approval process. A formal licence may be required if a substantive change to the highway is sought or where the proposal is otherwise not compliant with the original legal obligations.

Thats just the first couple of paragraphs, it goes on about listed structures, amongst other issues. The bit above about avoidable hazards to traffic is interesting.

 

[Davester50]

Ok, so not so simple! Shame, as superficially it looks like a reasonable option.

 

[Irascible]

Instead of spending what'd be somewhat over £1bn on a new line over the old route and then having to pay the upkeep for it not to be used 99% of the year, can we not spend £1bn going around weakpoints like low bridges and flood risks? what happens in the next south-west storm when there's waves smashing Dawlish *and* Cowley Bridge floods again? fat lot of good Okehampton-Tavistock would be then. I'm also not sure what that line would have done for those people stranded in Totnes either. If only Plymouth still had an airport even the roads out aren't exactly amazing.

I don't know anything about brick bridges - is there some way of strengthening them against strikes like this? would bolts right through from one side of the arch to the other have helped or would that just meant both sides of the bridge moved?

 

[Nova1]

Instead of spending what'd be somewhat over £1bn on a new line over the old route and then having to pay the upkeep for it not to be used 99% of the year, can we not spend £1bn going around weakpoints like low bridges and flood risks? what happens in the next south-west storm when there's waves smashing Dawlish *and* Cowley Bridge floods again? fat lot of good Okehampton-Tavistock would be then. I'm also not sure what that line would have done for those people stranded in Totnes either. If only Plymouth still had an airport even the roads out aren't exactly amazing.

I don't know anything about brick bridges - is there some way of strengthening them against strikes like this? would bolts right through from one side of the arch to the other have helped or would that just meant both sides of the bridge moved?

Well there's just been a complete overhaul on the Dawlish sea wall

 

[irish_rail]

Having lived in Plymouth for sometime, I think that the issue is that the insular nature of the place leads the locals to believe that it's more important than it actually is, ranked by population its the 30th largest UK conurbation alongside the likes of Luton and Southend on Sea.

Population of Southend is 183,000
Population of Plymouth is 264,000

And I think you'll find Plymouth is rather higher up the table than 30th.

On the Western, only Cardiff and Bristol are bigger.

 

[Irascible]

Well there's just been a complete overhaul on the Dawlish sea wall

Yep - talk of Dawlish was just an illustration that that sort of storm tends to hurt elsewhere too. Noone ever seems to mention spending on Cowley Bridge ( or immediately up the Exe from it ) despite how important it is.

--

Plymouth itself is slightly larger than Wolverhampton & Derby to give two examples, iirc. You should quite possibly include a lot of Cornwall in it's catchement area too.

 

[Robertj21a]

Population of Southend is 183,000
Population of Plymouth is 264,000

And I think you'll find Plymouth is rather higher up the table than 30th.

On the Western, only Cardiff and Bristol are bigger.

You're right, it's actually 29th.

 

[irish_rail]

You're right, it's actually 29th.

Well it depends which list you look at , as it is given as 16th in the table I saw a year or so ago. Just looked at another "league table" which has Plymouth at 23.
I think it depends how the figures are processed and massaged to be fair, and it is quite obvious there is no definitive list , id guess that somewhere between 16th and 30th is most accurate.

 

[Dai Corner]

Well it depends which list you look at , as it is given as 16th in the table I saw a year or so ago. Just looked at another "league table" which has Plymouth at 23.
I think it depends how the figures are processed and massaged to be fair, and it is quite obvious there is no definitive list , id guess that somewhere between 16th and 30th is most accurate.

The National Statistics Office use the concept of "buiilt-up areas".

the definition follows a ‘bricks and mortar’ approach, with areas defined as built-up land with a minimum area of 20 hectares (200,000 m2), while settlements within 200 metres of each other are linked. Built-up area sub-divisions are also identified to provide greater detail in the data, especially in the larger conurbations.

Plymouth comes out as the 30th largest using the 2011 census data.

 

[Western Sunset]

On the Western, only Cardiff and Bristol are bigger.

I think London might be slightly larger than both of those...

 

[Dai Corner]

I think London might be slightly larger than both of those...

Also Reading and Newport, using the ONS methodology.

 

[Martin_1981]

At the risk of pushing this thread into proper Crayonista territory, would a solution to this (probably uncommon) situation be a loco based at Plymouth that could be attached to the up service in the evening to take the sleeper up 'round Dartmoor, detach at Exeter, and reattached to the down service in the morning for the return trip?

Could the same loco not be used throughout and run round at both Plymouth and Exeter? After all, the sleeper sometimes reverses at Exeter on Sunday night/Monday mornings and travels via Honiton and Yeovil.

 

[zwk500]

I don't know anything about brick bridges - is there some way of strengthening them against strikes like this? would bolts right through from one side of the arch to the other have helped or would that just meant both sides of the bridge moved?

On a technical note its masonry not brick, but I think strengthening bolts would not have helped in this instance as the lorry broke the mortar joints. But I'm neither a builder nor a structural engineer so I'm sure somebody will correct me.

 

[Charlie Smythe]

Could the same loco not be used throughout and run round at both Plymouth and Exeter? After all, the sleeper sometimes reverses at Exeter on Sunday night/Monday mornings and travels via Honiton and Yeovil.

It’s a pain in the backside these days to run around as you need a shunter etc and not everywhere has one and all that. Reality it anyone with hands can do hand signals for a driver and the driver himself should know how to couple the loco to the train.

This is one aspect of the railway that is over complicated to the point where it’s counterproductive. Any member of staff could do handsigbals and the driver can couple himself. Would save time and money

 

[ExRes]

How much would it cost to brick up all these bridges so dumb lorry and bus drivers can't get stuck under them at all?

 

[Master29]

Having lived in Plymouth for sometime, I think that the issue is that the insular nature of the place leads the locals to believe that it's more important than it actually is, ranked by population its the 30th largest UK conurbation alongside the likes of Luton and Southend on Sea.

That's a very narrow comment really. You're effectively saying this is the people that live there's fault. That sort of thing exists all over the country and isn't very helpful. It also doesn't answer the question of the railways being treated shabbily over the years by successive governments. True, at certain times of the year Devon and Cornwall relax somewhat in numbers but as anyone else from down here will tell you the area has far more all year round tourism than before. It's not about being insular, it's about a decent railways service which in many areas sadly we don't have.

 

[Dai Corner]

That's a very narrow comment really. You're effectively saying this is the people that live there's fault. That sort of thing exists all over the country and isn't very helpful. It also doesn't answer the question of the railways being treated shabbily over the years by successive governments. True, at certain times of the year Devon and Cornwall relax somewhat in numbers but as anyone else from down here will tell you the area has far more all year round tourism than before. It's not about being insular, it's about a decent railways service which in many areas sadly we don't have.

Plymouth has an hourly service to/from London plus local trains to Devon and Cornwall and the sleeper. This seems comparable to or better than similarly sized conurbations outside south-east England like Swansea, Newport, Derby, Blackpool and Barnsley.

 

[RPI]

Plymouth has an hourly service to/from London plus local trains to Devon and Cornwall and the sleeper. This seems comparable to or better than similarly sized conurbations outside south-east England like Swansea, Newport, Derby, Blackpool and Barnsley.

Not to mention hourly Crosscountry services to Bristol, Birmingham and the North

 

[Master29]

Plymouth has an hourly service to/from London plus local trains to Devon and Cornwall and the sleeper. This seems comparable to or better than similarly sized conurbations outside south-east England like Swansea, Newport, Derby, Blackpool and Barnsley.

Many of which are short formed at the moment due to unreliability of stock. Crosscountry has only one service a day in Cornwall.

 

[RPI]

Many of which are short formed at the moment due to unreliability of stock. Crosscountry has only one service a day in Cornwall.

One a day to Cornwall but hourly north (actually, there is a 2 hour gap currently in the afternoon since covid) I've not seen a huge amount of 5 vice 10 IET'S lately, plenty of 9 vice 10 but that can't really be classed as a short formation as a 10 car only has about 4 more seats than a 9 car.

 

[Master29]

One a day to Cornwall but hourly north (actually, there is a 2 hour gap currently in the afternoon since covid) I've not seen a huge amount of 5 vice 10 IET'S lately, plenty of 9 vice 10 but that can't really be classed as a short formation as a 10 car only has about 4 more seats than a 9 car.

Indeed but the negligible seating difference between is hardly relevant here as I haven't seen many 9 car instead of 10 car IET's, whereas there have been plenty of 5 car trains from Paddington through to Penzance. Is this what you mean by 9 vice 10? There have been many more 9 and 10 car formations as you rightly point out but that has been necessary for a while now.

 

[SuspectUsual]

How much would it cost to brick up all these bridges so dumb lorry and bus drivers can't get stuck under them at all?

So the answer to the 0.00001% is to penalise the 99.99999%?

 

[Killingworth]

Returning for a moment to this particular bridge and the latest strike. The pictures on Google clearly show previous strikes and scrapes, all apparently from the same direction, up hill. That's bound to cause more damage as the truck acts like a wedge.

The approach from the uphill side has the correct signage but the arch appears deceptively high. A driver's attention will be drawn to the road narrowing, the gradient uphill and what might be coming the other way.

Major expenditure is being suggested to prevent a repetition. Surely all that's needed is to mount the restriction warning signs on a simple bar at the height of the lower portal at the other side.. It doesn't need to be substantial. By lowering the signage any vehicle approaching would have it more in their sight line to see it's relevance, and if they did proceed they'd hit a light bar and do little damage to the bridge.

 

[Grumpy Git]

How much would it cost to brick up all these bridges so dumb lorry and bus drivers can't get stuck under them at all?

Er, I think you'll find that's called an embankment.

 

[tiptoptaff]

It’s a pain in the backside these days to run around as you need a shunter etc and not everywhere has one and all that. Reality it anyone with hands can do hand signals for a driver and the driver himself should know how to couple the loco to the train.

This is one aspect of the railway that is over complicated to the point where it’s counterproductive. Any member of staff could do handsigbals and the driver can couple himself. Would save time and money

It's done by the Train Manager when it runs round at Exeter. But only a handful are so trained as its such a rare occurrence

 

[MotCO]

Major expenditure is being suggested to prevent a repetition. Surely all that's needed is to mount the restriction warning signs on a simple bar at the height of the lower portal at the other side.. It doesn't need to be substantial. By lowering the signage any vehicle approaching would have it more in their sight line to see it's relevance, and if they did proceed they'd hit a light bar and do little damage to the bridge.

That would certainly help. Or how about a dummy infill under the arch to redude the headroom to a constant height throught the bridge? Then it would be obvious how high the bridge is coming from the downhill side of the bridge.

 

[Ashley Hill]

It's done by the Train Manager when it runs round at Exeter. But only a handful are so trained as its such a rare occurrence

All are trained but many newer ones don't like getting their hands dirty so should really have stayed in the unit links. For planned run-rounds there's a volunteer list for those willing to do proper railway work.

 

[philthetube]

here is one: https://www.google.com/maps/@51.992...4!1si4ezWUcSch5NXRYla0rxTg!2e0!7i13312!8i6656 on the Hitchin-Cambridge line.

It can't be done everywhere, as you've got to have a sufficiently strong structure that something clanging the beam won't get the bridge at the same time, and I'm not aware of any on arches (although there's probably some). The criteria for fitting are a combination of frequency of being bashed, strength of the bridge, and potential disruption to rail traffic, but I don't know how individual decisions are made.

Returning for a moment to this particular bridge and the latest strike. The pictures on Google clearly show previous strikes and scrapes, all apparently from the same direction, up hill. That's bound to cause more damage as the truck acts like a wedge.

The approach from the uphill side has the correct signage but the arch appears deceptively high. A driver's attention will be drawn to the road narrowing, the gradient uphill and what might be coming the other way.

Major expenditure is being suggested to prevent a repetition. Surely all that's needed is to mount the restriction warning signs on a simple bar at the height of the lower portal at the other side.. It doesn't need to be substantial. By lowering the signage any vehicle approaching would have it more in their sight line to see it's relevance, and if they did proceed they'd hit a light bar and do little damage to the bridge.

There is no need for any real substance to a warning hanging from the bridge, chains would do, anything which needs a bang to alert drivers, this bridge is unusual in that the solution would not work in many places.

 

[zwk500]

There is no need for any real substance to a warning hanging from the bridge, chains would do, anything which needs a bang to alert drivers, this bridge is unusual in that the solution would not work in many places.

I did suggest this upthread, something similar to these: https://www.google.com/maps/@51.498...4!1szenbqwR4ZAkjGDW5uXHobA!2e0!7i13312!8i6656