Suggestions for where new flyovers/diveunders should be built to replace 'flat' junctions

[Cricketer8for9]

Can I put a vote in for Balham, and of course Windmill Bridge north of East Croydon.

 

[Stopper]

Absolutely. Particularly Hyndland East. 14 trains per hour, each way, every hour, over a flat junction!.

Also, Newbridge will be 12tph soon, currently 10tp. Both of those could do with one. A flyover at Newbridge may remove the need for the Almond chord, if possible.

 

[Bald Rick]

To answer the OPs question precisely, ie ‘the most compelling case’ you will need to understand the benefits of such a flying junction.

Typically the most benefits arise from enabling additional trains to run. Journey time improvements and reliability gains help, but it is more capacity that wins the argument. Crucially that extra capacity has to be useable, ie there is spare capacity elsewhere on the network and the flying junction unlocks it. And, the more valuable each train path is the better, valuable being determined by number of passengers on the train and the likely average fare they pay.

So the answer is going to be a junction that is a key bottleneck which if resolved will enable more, long trains that will travel on a high value route.

It’s a toss up between Woking and Windmill Bridge Junction. Both in development now.

 

[Joseph_Locke]

Woking appears to be winning the argument at the moment; any naysayers?

Castlefield Junction, Ordsall Lane Junction and Edgeley Junction.

 

[HowardGWR]

Yes I follow Bald_Rick's reasoning. I was going to suggest gathering of data in order to prioritise schemes, such as number of potential conflicts per hour, delays experienced, average length of delay, number of pax affected, and so on, but that does resolve in the points B_R is making. One factor that is taken into account with road schemes is the type of traveller. Solving delays to people on work duties is worth an awful lot more revenue benefit than commuters (they could just learn to get up in the morning earlier) and the bottom rung of benefit value is occupied by leisure seekers and shoppers.

Of course commuters don't drive the train, so if they are at work on their laptops then they are not travelling to work but are at work. Car drivers can't work so perhaps robot driven cars will change that one in future.

On the cost side, there is the difficulty of construction that could make a scheme a poor performer. I got from others here that Woking could be very expensive.

Windmill Bridge looks favourite.

 

[Taunton]

I recall going up the ECML, probably late 1980s, and at the Newark crossing there was the heavy plant building substantial earthworks going in alongside the Nottingham-Lincoln line. I thought the flyover was at last being built, that I somehow had not heard of.

Only subsequently did I find that it was not a rail project at all, but the new A46 bypass, which closely parallels the rail line. So a new road could be justified, but not a relief to the rail crossing.

It had been the same when the new Severn Bridge was under review in the early 1990s. Here was a chance to integrate road and rail, and abandon the nuisance in many senses Severn Tunnel, which is closely parallel. But the Dept for Transport does not think like that. I discussed it with the new bridge team at the design stage. Completely blank faces.

It’s a toss up between Woking and Windmill Bridge Junction. Both in development now.

I understand the bit about what additional service can be justified. But isn't the SWML full from Woking into Waterloo?

 

[Ianno87]

Indeed, but I was led to believe Woking provided a particular headache. Four conflicts an hour and all that, then having to make that work once you get closer to London.

The entire SWML Fast Line pattern is written around:
-4tph Waterloo-Haslemere/Portsmouth parallel moving at Woking every 15 minutes.
-Dorchester-Wareham single line
-West of England single line

The former is by far the most particularly binding being on the busiest part (the single lines you effectively have the option of playing with stopping patterns along the way)

 

[bluenoxid]

Where the Ilkley line splits from the Leeds to Shipley line near Apperley Bridge. I know it isn’t that compelling.

 

[swt_passenger]

I understand the bit about what additional service can be justified. But isn't the SWML full from Woking into Waterloo?

At a cursory glance the Wessex route study seems to justify it as a CP6 project for overall service reliability purposes, and a modest increase (2tph) in services by using the currently unused ‘firebreak paths’.

 

[lancastrian]

My personal choice would be Werrington, north of Peterborough, Colwich, Euxton and Doncaster South between the Sheffield & east Coast Lines and Doncaster North between the East Coast and North Lincolnshire lines.

 

[snowball]

Only subsequently did I find that it was not a rail project at all, but the new A46 bypass, which closely parallels the rail line. So a new road could be justified, but not a relief to the rail crossing.

There is now a scheme in the road programme to dual the A46 Newark bypass (currently the only single carriageway section of an otherwise dual carriageway and motorway route from Warwick to Lincoln). So there's another chance for coordination.

 

[Bald Rick]

I recall going up the ECML, probably late 1980s, and at the Newark crossing there was the heavy plant building substantial earthworks going in alongside the Nottingham-Lincoln line. I thought the flyover was at last being built, that I somehow had not heard of.

Only subsequently did I find that it was not a rail project at all, but the new A46 bypass, which closely parallels the rail line. So a new road could be justified, but not a relief to the rail crossing.

It had been the same when the new Severn Bridge was under review in the early 1990s. Here was a chance to integrate road and rail, and abandon the nuisance in many senses Severn Tunnel, which is closely parallel. But the Dept for Transport does not think like that. I discussed it with the new bridge team at the design stage. Completely blank faces.



I understand the bit about what additional service can be justified. But isn't the SWML full from Woking into Waterloo?

The thing about Newark is that it doesn’t enable any more paths, or at least not long distance on the ECML; the constraints are elsewhere: the 2/3 track section Peterborough to Huntingdon, Welwyn Viaduct (or Welwyn North station depending on your viewpoint), Doncaster, etc. I suspect you could run more paths from Nottingham to Lincoln, but bluntly a 2-3 car DMU on regional fares doth butter no parsnips.

As others have said, another 2 peak paths an hour into Waterloo are possible if Woking is done. As for the flyover itself it’s not that difficult, at least not compared to Windmill bridge.

 

[xotGD]

Darlington - so that trains to/from Bish don't have to cross the ECML

 

[Taunton]

The thing about Newark is that it doesn’t enable any more paths, or at least not long distance on the ECML; the constraints are elsewhere: the 2/3 track section Peterborough to Huntingdon, Welwyn Viaduct (or Welwyn North station depending on your viewpoint), Doncaster, etc.

So we wonder what additional paths have been created by the recent Shaftholme Junction flyover over the ECML, at a point much less busy than Newark, whose opening coincided with the closure of the coal flow from Immingham to the power stations which it was built to handle.

 

[306024]

How about (just for fun as money is no object) a flying junction to take the up Lea Valley Line at Copper Mill Jn over the line from Stratford to Tottenham Hale, and continuing under the Chingford line to rejoin the up Chingford Line at Clapton Jn. A roller coaster ride but removes two conflicts in one hit. Or will Crossrail 2 come to the rescue? .......

 

[The Ham]

I understand the bit about what additional service can be justified. But isn't the SWML full from Woking into Waterloo?

The short answer is yes, sort of.

The longer answer is yes, but there's plans for 4tph to Heathrow (2 to Guildford and 2 to Basingstoke) and you'd also be able to potentially run the Woking Stoppers to Guildford.

Then there's the advantage that you remove points of conflict which makes recovering from problems easier.

You could even look at providing a new Guildford to Basingstoke service (doubling back at Woking), although to be fair that's very unlikely.

My vote may appear to be a bit of a curve ball suggestion, but it would be to build a new junction to allow trains to run Basingstoke to Ascot via Farnborough. Why? It allows you to divert trains past Woking while you build the new junction there (there are other benefits too, such as better connections to/from Frimley and Camberley, including to Waterloo even though the junction would be facing the wrong way for direct services as well as potentially allowing more stations to be built and served without showing down existing services and increasing frequencies on local services).

 

[Adsy125]

The entire SWML Fast Line pattern is written around:
-4tph Waterloo-Haslemere/Portsmouth parallel moving at Woking every 15 minutes.
-Dorchester-Wareham single line
-West of England single line

The former is by far the most particularly binding being on the busiest part (the single lines you effectively have the option of playing with stopping patterns along the way)

The only single track bit is between Moreton and Dorchester South, luckily not all the way to Wareham!

 

[Bald Rick]

This thread has made me think; we have built / rebuilt / created rather a lot of grade separate junctions on the existing network (ie not on HS1, nor on the new Crossrail infrastructure) in the last decade or so. In no particular order:

Hitchin
Joan Croft
Allington (slight cheat, but it is effectively a new grade separation)
Acton
Airport Jn II
Reading x 3 (technically 3, operationally 4)
Bermondsey (technically 1, operationally 2)
Nuneaton + the down chord (worth half a point)
Shortlands
Norton Bridge

Any others?

 

[infobleep]

Whether it's needed or possible I know not but I'd like a flyover at the junction past Preston Park to Hove. Then it woild be possible to run direct trains on the morning to Hove avoiding Brighton.

Currently it can't be done as it means crossing the up line and too many trains use that in the morning to allow such a conflicting move.

 

[Bald Rick]

How about (just for fun as money is no object) a flying junction to take the up Lea Valley Line at Copper Mill Jn over the line from Stratford to Tottenham Hale, and continuing under the Chingford line to rejoin the up Chingford Line at Clapton Jn. A roller coaster ride but removes two conflicts in one hit. Or will Crossrail 2 come to the rescue? .......

Pretty sure thats was looked at years ago. It’s not pretty. Has to be a flyover the whole way as it’s all marsh (and protected marsh at that). Unlikely to happen I’d have thought.

 

[swt_passenger]

This thread has made me think; we have built / rebuilt / created rather a lot of grade separate junctions on the existing network (ie not on HS1, nor on the new Crossrail infrastructure) in the last decade or so. In no particular order:
...
Any others?

Canal tunnels at St Pancras end?

 

[Jonny]

Darlington - so that trains to/from Bish don't have to cross the ECML

Agree, but to be pedantic...
Technically it's all the trains from the Dinsdale direction. Bishop Auckland to platform 4 does not directly cross anything ECML.

 

[306024]

Pretty sure thats been looked at. It’s not pretty. Has to be a flyover the whole way as it’s all marsh (and protected marsh at that). Unlikely to happen I’d have thought.

It has and it wasn’t pretty, and one proposal was unnecessarily complex. The West Anglia route has a number of flat junction conflicts to resolve in short succession. After Liverpool St throat there is Bethnal Green North Jn, Hackney Downs, Clapton Jn and Copper Mill Jn. All can be timetabled (obviously) but it is all quite tight. ECS paths to Chingford CS being a particular challenge.

 

[Ianno87]

This thread has made me think; we have built / rebuilt / created rather a lot of grade separate junctions on the existing network (ie not on HS1, nor on the new Crossrail infrastructure) in the last decade or so. In no particular order:

Hitchin
Joan Croft
Allington (slight cheat, but it is effectively a new grade separation)
Acton
Airport Jn II
Reading x 3 (technically 3, operationally 4)
Bermondsey (technically 1, operationally 2)
Nuneaton + the down chord (worth half a point)
Shortlands
Norton Bridge

Any others?

Rugby remodelling wasn't grade separation as such, but reconfigured the layout to make better use of the grade separation already there

 

[swt_passenger]

My vote may appear to be a bit of a curve ball suggestion, but it would be to build a new junction to allow trains to run Basingstoke to Ascot via Farnborough. Why? It allows you to divert trains past Woking while you build the new junction there (there are other benefits too, such as better connections to/from Frimley and Camberley, including to Waterloo even though the junction would be facing the wrong way for direct services as well as potentially allowing more stations to be built and served without showing down existing services and increasing frequencies on local services).

I think you overplay the difficulty of building the Woking flyover. Having watched them build all the new stuff at Reading, Woking would appear simpler all round. Only single track needed for a start. Whatever the merits of your suggestion, and in a national priority list i think it’d be very low, I don’t think you can hang build-ability of Woking on it...

 

[backontrack]

Only subsequently did I find that it was not a rail project at all, but the new A46 bypass, which closely parallels the rail line. So a new road could be justified, but not a relief to the rail crossing.

It had been the same when the new Severn Bridge was under review in the early 1990s. Here was a chance to integrate road and rail, and abandon the nuisance in many senses Severn Tunnel, which is closely parallel. But the Dept for Transport does not think like that. I discussed it with the new bridge team at the design stage. Completely blank faces.

That's a bit like the bad decision not to include a rail option when the Dornoch Firth Bridge was built.

 

[Dr Hoo]

Rugby remodelling wasn't grade separation as such, but reconfigured the layout to make better use of the grade separation already there

The Proof House Junction re-modelling at Birmingham also made much better use of the existing grade separations.

 

[Dr Hoo]

This thread has made me think; we have built / rebuilt / created rather a lot of grade separate junctions on the existing network (ie not on HS1, nor on the new Crossrail infrastructure) in the last decade or so. In no particular order:

Hitchin
Joan Croft
Allington (slight cheat, but it is effectively a new grade separation)
Acton
Airport Jn II
Reading x 3 (technically 3, operationally 4)
Bermondsey (technically 1, operationally 2)
Nuneaton + the down chord (worth half a point)
Shortlands
Norton Bridge

Any others?

Several effective grade separations around the London Overground from Highbury to Clapham Junction via Surrey Quays, albeit with several busier flat junctions too.

 

[IanXC]

Doncaster is an unfortunate set of circumstances. With both the Skellow route from Adwick to Hatfield and Stainforth and the Doncaster North Chord so near but yet so far from solving the passenger train problem!

That said, even with the journey time penalty (approximately 12 minutes extra Doncaster to Hatfield and Stainforth) should additional stopping capacity be required from Doncaster towards (either) Thorne then Skellow would probably be suitable if finding a path crossing the ECML was not possible.

 

[snowball]

Airport Jn II

Any others?

You could say that what we've had recently is Airport Jn II and III.