SEVERN TUNNEL JUNCTION - Connection to M4.

[Llanigraham]

It's worth noting though that the difficult geology came as a surprise when the tunnels were originally bored. Now that we have a much better idea of what the builders would be facing - and with that new technology you mentioned - I am fairly confident that they could bore another tunnel, or rebore the existing ones in months rather than years.

Possibly, but what happens in that period whilst the M4 is closed?

 

[PMN1]

Boring two new tunnels was looked at back in 2007-2011

http://www.bbc.co.uk/news/uk-wales-politics-17264422

 

[najaB]

Possibly, but what happens in that period whilst the M4 is closed?

I don't have an answer for that, I was just pointing out that it wouldn't take as long these days as it did in the 60's.

 

[Llanigraham]

I don't have an answer for that, I was just pointing out that it wouldn't take as long these days as it did in the 60's.

The fact is that it would now be impossible to shut the M4 at Brynglas Tunnels for anything more than a couple of hours without bringing the whole of Newport to a grinding halt. Even closing one of the bores for a couple of hours results in massive queues in both directions.

 

[HSTEd]

The South motorway is expensive but it is the only reasonable solution that doesn't bring everything to a grinding halt.

Boring tunnels is going to collapse the entire system - and public transport would take years to even start to reduce the problems, there is massive cultural inertia to overcome.

 

[Greenback]

I have worked with a team who are based in Swansea and Bedwas for the last 6 years I've never heard any comment from them about traffic congestion around Newport.

It's reassuring that there are others who haven't heard a lot of complaints from people that they know and work with.

No doubt it's bad at rush hour but that's the same everywhere.

Indeed. I'm afraid that, just as trains are busier at certain times, and some will have to stand, so it is that roads are also busier at peak times and there will eb congestion and delay/

All too often those demanding action believe that their problem is unique and there being disadvantaged in comparison with other areas and there's a magic construction based solution. No doubt there's plenty of folk in Swansea, Llanelli and the Valleys who see their local problem as a higher priority.

Exactly right. While I appreciate that there is a problem, which has been caused by the geography of the area and the fact that the M4 was built with only two lanes, I do wonder whether building a new motorway will alleviate the issue or simply funnel the congestion on to the access roads instead.

It seems to have been proven down the decades that, as far as roads are concerned, you can't build your way out of trouble.

Regarding the posts about pop shows and sports events, the notion one should build a new motorway for these is economic madness. Promoters should institute environmentally sustainable transport plans and make it clear to attenders that public transport is the only way to access them. It can be done. as other venues demonstrate. Building roads (or indeed, sometimes, expanding railways) to cater for rush hour commuters is also nuts. We really have to start using some forward thinking on these issues and the Newport case is no exception.

I agree with you. So, it seems, do many politicians. It won't be easy, but I'm sure something can be done.

 

[jimm]

Regarding the posts about pop shows and sports events, the notion one should build a new motorway for these is economic madness. Promoters should institute environmentally sustainable transport plans and make it clear to attenders that public transport is the only way to access them. It can be done. as other venues demonstrate. Building roads (or indeed, sometimes, expanding railways) to cater for rush hour commuters is also nuts. We really have to start using some forward thinking on these issues and the Newport case is no exception.

So how are all the rush-hour commuters supposed to get places then? Many of which will not have any public transport access, never mind rail services.

I await your "forward-thinking" proposals for ensuring that "public transport is the only way to access" events at the Millennium Stadium, which are just one of the things that cause congestion in Newport. Others include the inadequate two-lane section of the M% through Newport and the tunnels.

It's all very well making sweeping statements, but what practical steps do you suggest?

How much bigger will Cardiff Central have to be to handle the passengers, where is the extra rolling stock coming from, which roads will handle all the extra buses that your nirvana would require, etc, etc?

It's worth noting though that the difficult geology came as a surprise when the tunnels were originally bored. Now that we have a much better idea of what the builders would be facing - and with that new technology you mentioned - I am fairly confident that they could bore another tunnel, or rebore the existing ones in months rather than years.

And your qualifications for saying this are what? Are you a tunnelling engineer?

I refer you to the Farnworth Tunnel reboring project, where presumably they thought they knew all about the ground conditions...

Network Rail has confirmed that the work on Farnworth Tunnel is to be extended beyond the original completion date of Sunday 04 October, possibly until December/January.

The reason for this is due to exceptionally poor ground conditions and unforeseen running sands which the machine has come across during boring. This is slowing the excavation speed and creating voids which need filling with specialist grout before boring can safely continue.

http://www.tpexpress.co.uk/your-journey/farnworth-tunnel/

 

[HSTfan!!!]

All well and good saying close junctions in rush hour to prevent local traffic clogging up the m4 but Newport is frequently grid locked as it is, you're just going to make the problem driving through the city worse than it already is.

 

[Michael.Y]

The fact is that it would now be impossible to shut the M4 at Brynglas Tunnels for anything more than a couple of hours without bringing the whole of Newport to a grinding halt. Even closing one of the bores for a couple of hours results in massive queues in both directions.

It's been closed several times overnight and a contraflow put in with no discernable problem.

 

[Llanigraham]

It's been closed several times overnight and a contraflow put in with no discernable problem.

OFGS!!
AT NIGHT!!
A bit different to the traffic you will find between 0730 and 1930 in the day time.

Do you have any experience of this section of road?
Do you live in the area?
Somehow I doubt it.

 

[Michael.Y]

OFGS!!
AT NIGHT!!
A bit different to the traffic you will find between 0730 and 1930 in the day time.

Do you have any experience of this section of road?
Do you live in the area?
Somehow I doubt it.

Yes... you re-open it during the day....

 

[jimm]

Yes... you re-open it during the day....

Sorry, but if you are going to have a socking great machine reboring a tunnel, you can't just haul it out at 5am and let traffic back in.

Even if you were allowed to rebore one tunnel with the other open to traffic - and I'd have my doubts about that, given their proximity - the one that was open would have one lane available in each direction. That'd work well...

 

[Llanigraham]

Yes... you re-open it during the day....

What??
How are you going to reopen a part built tunnel each day?

Sorry, but you quite obviously have no idea of how these things are done, or the area we are discussing!!
I ask again; where are you in the UK?

I suggest that you read the thread about Farnsworth Tunnel to give you a little inkling of the problems involved.

 

[PMN1]

The BBC article suggests two new tunnels would be bored to join the existing ones. Be interesting to see if anything more than a casual glance at a map was done to see if they could be shoehorned in.

 

[EbbwJunction1]

The BBC article suggests two new tunnels would be bored to join the existing ones. Be interesting to see if anything more than a casual glance at a map was done to see if they could be shoehorned in.

Well, above the existing tunnels, there are the beginnings of a fairly large housing estate called Brynglas.

There are two main access roads, Brynglas Road and Brynglas Avenue. The former didn't seem to have suffered from the work done for the original tunnels, but the latter certainly did.

From memory and a quick look at Google Maps, about a dozen homes were demolished on the left hand side of the road, with about four or five on the other side. Even if the techniques of building tunnels have improved in the thirty or so years since they were built, the ground conditions are almost certainly the same, and any excavation on the site would be very risky for the local residents.

The other problem is that there's lots of natural obstacles (not to say local businesses and houses) on the level of the current motorway that would need to be removed (if it were possible) to allow the current motorway to be widened.

The east of the site is very near to the River Usk, and this is crossed by a bridge. Very near to it and running from north to south is the A4042 which is an elevated section at that stage and is also linked into the motorway as a junction. So, you'd need to bridge the Usk and find someway of going under the A4042.

On the south and west of the current tunnels are quite a few houses and businesses which would need to be demolished. Again, the road would have to go under the A4042.

Whilst in theory the widening of the exiting tunnels would appear to be the most logical way, it really isn't that simple. I have to say that I'm not 100% certain that the southern option is the best, but it looks as if it would certainly be easier to build than new tunnels.

Oh, who and where am I? A fairly local resident (albeit on the other side of Newport), that's who!

 

[PMN1]

Well, above the existing tunnels, there are the beginnings of a fairly large housing estate called Brynglas.

There are two main access roads, Brynglas Road and Brynglas Avenue. The former didn't seem to have suffered from the work done for the original tunnels, but the latter certainly did.

From memory and a quick look at Google Maps, about a dozen homes were demolished on the left hand side of the road, with about four or five on the other side. Even if the techniques of building tunnels have improved in the thirty or so years since they were built, the ground conditions are almost certainly the same, and any excavation on the site would be very risky for the local residents.

The other problem is that there's lots of natural obstacles (not to say local businesses and houses) on the level of the current motorway that would need to be removed (if it were possible) to allow the current motorway to be widened.

The east of the site is very near to the River Usk, and this is crossed by a bridge. Very near to it and running from north to south is the A4042 which is an elevated section at that stage and is also linked into the motorway as a junction. So, you'd need to bridge the Usk and find someway of going under the A4042.

On the south and west of the current tunnels are quite a few houses and businesses which would need to be demolished. Again, the road would have to go under the A4042.

Whilst in theory the widening of the exiting tunnels would appear to be the most logical way, it really isn't that simple. I have to say that I'm not 100% certain that the southern option is the best, but it looks as if it would certainly be easier to build than new tunnels.

Oh I know what the grounds like, I live in Abergavenny, that's why I was interested in where they thought they could put two new tunnels.