Bridge bashing

[Nick C]

Netowrk Rail have published the latest "most bashed" chart:

 

https://www.bbc.co.uk/news/uk-england-leicestershire-54871244

[smithlington smithe]

 

And Scotland’s take on the subject 

https://t.co/qSEo8Rv42Z

Edited November 10, 2020 by smithlington smithe

[melmerby]

 

On guided busway it says

Really?

https://www.bbc.co.uk/news/uk-england-cambridgeshire-54937076

[corneliuslundie]

There was no guided busway when I lived in Cambridge, Hills Road bridge goes over the railway. The busway is on the route of the old Oxford-Cambridge line- the height is about right.  But look at that height sign. How ever did the driver not see that the bridge was a couple of feet lower than the bus?

Jonathan

[JDW]

Obviously I don't know the full circumstances but considering that the bus is on the busway, I have to wonder how it came to be there. It had route C on the destination, assuming that route C normally goes that way, the drivers and controllers will all know and have been trained on the busway and know that it is single-deck route. Was it a double deck put on a journey that should only be single-deck? In which case why did the controller or driver not realise? Was the driver going the wrong way, should route C go that way? Again though, if s/he is a busway driver, s/he should not only be aware of the bridge but I'd expect him/her to know it's a single-deck only route. It seems a very odd one to me. 

[caradoc]

The photos quite clearly show that the bus, and the bridge, are on a normal road, not the guided busway; The vehicle seems to be one that does run on the busway, but it was not at this point. 

 

[stewartingram]

That is a section of route where only s/d buses go.

It is an extra "arch" that was put in under the Hills Road bridge, to allow the access road from the station forecourt to reach the busway section on the old Bletchley line formation. 

Bus route C changed from the 1st November 2018. Prior to this it was run by Whippet Coaches, with s/d buses, from St.Ives - Cambridge (I think Drummer St  in the City Centre).

Since 1/11/2020, Stagecoach (who run the other busway services) have introduced a route C from St.Ives-Cambridge Railway Station. This is to free up capacity on the s/s services on the busway, giving a 5 min interval peak service to Cambridge. The s/d buses continue from the station under this bridge. (Info taken from the busway website).

The bus in the pic looks to be one of the recently introduced six wheeled high capacity d/d buses, definitely prohibited beyond the station.

[JDW]

7 hours ago, caradoc said:

The photos quite clearly show that the bus, and the bridge, are on a normal road, not the guided busway; The vehicle seems to be one that does run on the busway, but it was not at this point. 

 

 

I know, I looked at the photos. I equally quite clearly didn't say it was on the guided busway section. It is a buses only road which forms part of the busway though. Hence my surprise at [seemingly] not just a driver but a controller sending a bus on a route which is very clearly single deck only. It's not like the ones where a driver is on diversion and goes down a side street and forgets about the bridge. It's a specific, single-deck only (and NO other vehicles) road. 

Edited November 14, 2020 by JDW

[corneliuslundie]

Thanks. I was not even half right about it being on the old railway alignment then. Sorry to confuse. I had accepted the early  statement that it was on the busway. And my memory of the geography is obviously not too good. Still one which shouldn't have happened though. And an expensive way to treat an expensive new bus. Just glad there were no casualties.

Jonathan

[caradoc]

1 hour ago, JDW said:

I know, I looked at the photos. I equally quite clearly didn't say it was on the guided busway section.

 

Fair enough, I just took it that busway referred to the guided busway, not a normal road reserved for buses, and from the look of things, bikes too !

[Wickham Green too]

Guided bikes ?

[corneliuslundie]

Not a new bridge bash, but a general question.

There have been numerous occasions when double deck buses have been scalped over the last few years. How fast would a bus have to be going to have its roof removed as neatly as that one recently in Cambridge? And what are the strength requirements for bus roofs? Not very onerous, it would seem? Presumably apart from incidents such as we have seen this does not matter.

Jonathan

[Busmansholiday]

The stopping distance for a car at 30 mph is 75 feet, or twice the length of that bus. So if you "forget" you are driving a double deck you'll be through the bridge before it stops. In terms of strength, there's very little in the top deck above the bottom of the windows. You have to remember that there are requirements for the bus to be able to tilt to 28 degrees without falling over so the majority of the weight and strength need to be low down.

[PhilJ W]

1 hour ago, Busmansholiday said:

The stopping distance for a car at 30 mph is 75 feet, or twice the length of that bus. So if you "forget" you are driving a double deck you'll be through the bridge before it stops. In terms of strength, there's very little in the top deck above the bottom of the windows. You have to remember that there are requirements for the bus to be able to tilt to 28 degrees without falling over so the majority of the weight and strength need to be low down.

And most of the strength is in the glass which being safety glass disintegrates when under stress. Either that or they are designed to be torn off rather than to cause a sudden stop. Buses often carry standing passengers and if one were to come to a sudden stop as in hitting a solid object the casualties would be greater.

[JDW]

In terms of how long it takes to stop, if you don't realise until you hit it then by the time you've realised, whacked the brakes, and come to a stop, you're going to be well under by the time you come to a stop, even though the thinking and moving your foot across might only take a second. 

In terms of how quickly you stop, of course there are lots of factors. At normal driving speeds with a hus in an urban area I'd say that from experience you can stop a single-decker in less than twice its own length if you have to, depending on the bus, road surface, etc. But you'll hurt a lot of people. I do remember once leaving a nice set of skid marks with a Leyland Olympian on a tarmac surface, after a car pulled right into my path...

 

As for bus roofs, I don't think they are subject to the same roll-over crashworthiness standards as coaches, and I seem to remember that they are designed to react that way as opposed to, say, having very solid front corners which would likely result in the roof being squashed backwards and downwards onto people, rather than all the pillars shearing and it beings pushed backwards. Though I may be wrong, it may just be the way they tend to react. 

[37114]

On 23/11/2020 at 11:31, PhilJ W said:

And most of the strength is in the glass which being safety glass disintegrates when under stress. Either that or they are designed to be torn off rather than to cause a sudden stop. Buses often carry standing passengers and if one were to come to a sudden stop as in hitting a solid object the casualties would be greater.

More recent designs have the roof deliberately designed to shear off as has been the case here, it is much safer for the passengers.  If you look at the Railtrack video filmed at the bridge in Swindon, it was hit by a 1970s Bristol VR. The roof crumpled and would have crushed the upper deck occupants.

[JDW]

Thanks, I thought that was indeed the case.

[Titan]

1 hour ago, JDW said:

As for bus roofs, I don't think they are subject to the same roll-over crashworthiness standards as coaches, and I seem to remember that they are designed to react that way as opposed to, say, having very solid front corners which would likely result in the roof being squashed backwards and downwards onto people, rather than all the pillars shearing and it beings pushed backwards. Though I may be wrong, it may just be the way they tend to react. 

 

It is quite difficult even getting a double decker on its side, getting it to roll over on to it's roof must be damn near impossible compared to a single decker or a coach, so I suspect that the roof has to be as lightweight as possible to achieve this. So it needs to be little more than just strong enough not to collapse under service conditions as a strong heavy roof is more likely to be detrimental to safety rather than improving it.

Edited November 24, 2020 by Titan

[JDW]

16 minutes ago, Titan said:

 

It is quite difficult even getting a double decker on its side, getting it to roll over on to it's roof must be damn near impossible compared to a single decker or a coach, so I suspect that the roof has to be as lightweight as possible to achieve this. So it needs to be little more than just strong enough not to collapse under service conditions as a strong heavy roof is more likely to be detrimental to safety rather than improving it.

 

Yes, exactly that. As you say weight is the big issue, hence why most double-deckers are single-glazed and why (for example) newer Wrightbus products have shallower windows upstairs. 

[roythebus]

A British built double decker rolled over in Belgium a few weeks ago. a Bristol Lodekka with Eastern Coachworks body, very substantially built! It was on a wedding job and in high winds got blown sideways, the right side wheels went off the road into a rather soggy field and the bus rolled onto its side landing next to a canal. Several people had minor injuries. the bus was recovered and had 2 broken windows. I happen to know the owner and operator of the bus! It's now back in service.

 

Double deckers have to tilt to 38 degress not 28 degrees as mentioned above.

[melmerby]

37 minutes ago, roythebus said:

 

 

Double deckers have to tilt to 38 degress not 28 degrees as mentioned above.

Not according to the data.

I think you will find it is 28 degrees for a Double deck bus with the bus fully laden on top.

 

Here is  a Wrightbus doing just that, quite clearly more than 28.

[Hobby]

On 23/11/2020 at 11:31, PhilJ W said:

Buses often carry standing passengers and if one were to come to a sudden stop as in hitting a solid object the casualties would be greater.

 

I'm pretty sure standing isn't allowed on the upper deck, though? Injuries wise if no-one is wearing a seat belt I suspect hitting the seat in front (mainly metal or hard plastic) would do as much harm as being thrown down the aisle, especially as there may well be other passengers in the aisle to lessen the impact.... All conjecture, though.

[petethemole]

I wouldn't want to be standing on the lower deck when a bus came to a sudden stop.  The person at the back might get off lightly; the one nearest the front would hurtle past the driver and hit the windscreen/bulkhead hard, very hard.  I was once on a bus, waiting to get off, so standing just behind the driver, when he did an emergency stop to avoid an idiot driver. I lost my balance and staggered forwards as far as the bulkhead.  The bus was in traffic, pulling away from the previous stop and only doing about 15mph.

[Busmansholiday]

Double deck 28 degrees, single 35 degree. As for stopping rapidly when not holding the provided grabs, I had a fight break out on the last bus (after the pubs closed) one night. I slammed on the brakes and the two idiots were very rapidly hitting the panel / windscreen next to me. I opened the doors and through them off whilst they were still winded !

[F-UnitMad]

4 hours ago, Busmansholiday said:

Double deck 28 degrees, single 35 degree. As for stopping rapidly when not holding the provided grabs, I had a fight break out on the last bus (after the pubs closed) one night. I slammed on the brakes and the two idiots were very rapidly hitting the panel / windscreen next to me. I opened the doors and through them off whilst they were still winded !

Thanks for reminding me why I didn't want to drive buses or coaches!! 52 back seat drivers??!!?? No thanks!!!