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New grade-separation if money/relocation were no object

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Inspired by this comment about grade separation in western Edinburgh:
Aye. Realistically if you were going to do it you’d probably end flattening the eastern end of Forrester Park Ave/Green/Drive. As I say, astronomically expensive and that’s assuming you could get the land at all.
If you had infinite money and didn't care about the human disruption for the people whose houses you might demolish (imagine you're playing a computer game!) where would you grade-separate first on the railway?
 
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AlastairFraser

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Inspired by this comment about grade separation in western Edinburgh:

If you had infinite money and didn't care about the human disruption for the people whose houses you might demolish (imagine you're playing a computer game!) where would you grade-separate first on the railway?
Didcot East Junction, with an additional N - S flyover providing for a rebuilt Didcot, Newbury and Southampton Railway.
8 tracking the Castlefield viaduct from Deansgate to Manchester Picc (4 tracks for HS3 on the top, 4 tracks for medium-distance services on the bottom level)
 

HSTEd

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Well if money is no object..... everything!

Flat junctions are the work of the devil.

But slightly more realistically, junctions at the west end of the Castlefield Corridor
 

Irascible

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Cowley Bridge Jct ( along with raising everything out of the floods ) - I would *love* to see how someone can manage that with what I think is a listed bridge there! ( probably better off moving Riverside yard & running the Barnstaple line into where it was ...).

I wonder how many edge cases there are that'd have problems eased by more bidirectional signalling, ie shifting the awkward crossover point rather than shifting the junction.
 

Mintona

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Didcot East and Wootton Bassett, and you’d basically have no delays anymore on the GWML. Well, maybe.
 

HST43257

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Skelton Bridge Jn
Northallerton LL link to ECML at nth end
Doncaster (Kirk Sandall line to Conisborough line, new platforms next to 8)
Salford Crescent
Edegely Jn
Blackfriars Jn
 

Minstral25

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Stoats Nest Junction to allow Main line services down through Redhill without conflicts
Same at Earlswood in reverse
 

HamworthyGoods

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Woking west end.

Basingstoke East End would appear higher up many people’s agenda.

The long freights running between the Midlands and Southampton crossing the layout slowly use up a lot more capacity than the Portsmouth trains joining the mainline at Woking.

Didcot East and Wootton Bassett, and you’d basically have no delays anymore on the GWML. Well, maybe.

Agreed with Didcot East, however I would have thought some of the flat junctions around Bristol / Bristol Parkway, even Bathampton have higher levels of traffic crossing than Wootton Bassett.
 

43096

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Well if money is no object..... everything!

Flat junctions are the work of the devil.

But slightly more realistically, junctions at the west end of the Castlefield Corridor
Slade Lane Junction needs sorting out for a start.
 

JonathanH

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Stoats Nest Junction to allow Main line services down through Redhill without conflicts
Same at Earlswood in reverse
I'd focus on Redhill itself before either of those.
Or South Croydon (or Purley for that matter) both of which would affect more trains on the Redhill route than Stoats Nest Junction although I appreciate that neither looks feasible.
 
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Snow1964

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Basingstoke East End would appear higher up many people’s agenda.

The long freights running between the Midlands and Southampton crossing the layout slowly use up a lot more capacity than the Portsmouth trains joining the mainline at Woking.



Agreed with Didcot East, however I would have thought some of the flat junctions around Bristol / Bristol Parkway, even Bathampton have higher levels of traffic crossing than Wootton Bassett.

Basingstoke East should also allow stopping trains returning to Waterloo to cross

Bathampton has a third track which at least allows trains to pass if one is waiting to cross junction, so not most critical

But Bristol parkway (both ends) would be good

I would add Redbridge (Southampton docks area)
 

TBY-Paul

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Ferryhill South or Tursdale junction to enable services to use the Stillington line.
 

waverley47

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So, I'm gonna go over a lot of what's already been said, but it's worth taking a look at the background for a lot of these. The most beneficial junctions to grade separate are functionally those with the highest number of conflicting moves per hour.

In the UK, the busiest single junction is actually the one at the south end of Blackfriars station, with up to 18 conflicting moves per hour, but that junction is relatively low speed, and the ATO in the core helps regulate everything so you don't lose any many paths in disruption. Yes, it would be great to grade separate the whole Thameslink Core, but it's not really top of the list.

Another popular one is Working West, which has space to grade separate already but has never been done. Here, there are four conflicting moves per hour, but they have to cross both the down fast and down slow, so they are far more likely to cause conflicts. The junction is also relatively fast, which means being late eats more paths. In fact, it's such a disruption that the whole of the Waterloo main line timetable is written around this one junction.

There are a couple of other important ones that are similar to woking, where there shouldn't be many conflicts, but the conflicts caused are very disruptive, and the junction acts as a constraint on timetabling for a wide area: Uddingston, Newton East, Law Jn and Newbridge in Scotland; Wigston, the north end of Sheffield, Euxton lane, Colwich, Basingstoke East, Wooton Bassett jn and a couple round Birmingham all need doing. These are disruptive if they go wrong, and constrain timetables too much in the 21st century to not be done.

Next there is the second category, big stations that need rebuilt to take in grade separation. The obvious one is Doncaster, but Stafford, Crewe, Stratford, Redhill and Coventry all suffer from this to various extents. These are places where simple grade separation wouldn't work, you'd need to completely rebuild the station in a way that had grade separated routes. At Doncaster for example, there are five possible conflicting routes, with trains in each direction conflicting which is unusual. A grand total of about 17 trains conflicting per hour is getting awfully close to every path conflicting with something else.

Finally there are the nice to haves. These are mainly in plain line and would be amazing if they already existed, but so unbelievably complex to build as to make them virtually impossible. The best example is Leadburn Jn, which I think only has 2tph crossing in each direction per hour, but they have to be timetabled perfectly. If one sneezes on the approach to this junction in the peaks, they'd screw up the timetable for the southern wcml.

Grade separation of a lot of the south London lines comes into this category; how for example could one even begin to imagine grade separation of Lewisham or Sutton, let alone Herne Hill or Tulse Hill? Manchester west end has the same problems.

Personally my vote is for Woking west: it's such a capacity constraint and it's quite likely to go wrong on any given day. Either that or building the almond chord to solve Newbridge and Haymarket East in one, but that's purely due to how much time I spend on trains, waiting for paths through the central belt.
 

D365

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Castlefield, Leicester, Newark in that order.
 

Minstral25

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I'd focus on Redhill itself before either of those.

Or South Croydon (or Purley for that matter) both of which would affect more trains on the Redhill route than Stoats Nest Junction although I appreciate that neither looks feasible.

It said money no object. :)

Redhill is restricted with services to 6tph because of the inability to get fast line trains through Redhill and the lack of paths on the slow lines south of Croydon. It is around 6-8 minutes slower via Redhill as well partially caused by difficulty crossing from fast to slow then back again. Releasing this constriction with flyovers would mean going via Redhill is much closer to the times achieved on the Quarry route. Thus more trains could run via Redhill and longer distance services could call again relinking Redhill with the coast. It is less than 50/50 if CARS could do that.

I agree that adding adjustments at Redhill is also a good idea as the entry speed and crossing moves add complication, but I'd do the flyovers first so enough trains can come down to create an issue at Redhill first. Otherwise pointless
 

Halish Railway

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Although not necessarily unrealistic due to the vast amount of land east of it, Apperley Junction which should include the increase of the linespeed of the diverging line to 70 mph as well as increasing the short stretch of 80 mph running on the up Shipley line to 90 mph.

There would be extra services added along the line between there and Leeds if the Otley & Skipton to Colne lines reopened. What makes this junction a bit of a pain is the presence of the feeder station, although this could be solved by having the junction the the east of the feeder station.
 

Bevan Price

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Rather too many to list here, but in North West England, roughly in order of priority:
1. Slade Lane Jn
2. Ordsall Lane Jn
3. Euxton Jn
4. Crewe, South & North ends.
5. Stockport, South end.
6. Ardwick Jn.
 

Peregrine 4903

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Surely if money is no object Lewisham would be the highest priority. Can't think of a more congested junction with some many different types of conflicting moves.

Grade seperating Tanners Hill Junction, Lewisham Vale Junction, St John's, Lewisham itself, Parks Bridge Junction the Courthill Junctions and Hither Green would surely by far the most beneficial if money was no object. Considering the really good signalling headways in Kent, this could allow you to run so many more services, especially as Cannon Street and particularly Victoria Eastern are nowhere near capcity.
 

zwk500

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In which direction?
Well money/consequences no object, so all :D

A (very slight) dose of realism - provide a bay platform on the Down side for the Tonbridge Services, then put the Up Slow on a flyover above the Guildford lines for a centre reversal.

Actual possibility for Grade-Separation: 0. Best to hope for is conflict-free Tonbridge-Redhill and Double-lead connection to permit parallel moves from the BML to Platforms 0-2.
 

Peregrine 4903

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Well money/consequences no object, so all :D

A (very slight) dose of realism - provide a bay platform on the Down side for the Tonbridge Services, then put the Up Slow on a flyover above the Guildford lines for a centre reversal.

Actual possibility for Grade-Separation: 0. Best to hope for is conflict-free Tonbridge-Redhill and Double-lead connection to permit parallel moves from the BML to Platforms 0-2.
Even just setting up a set of points to allow the Redhill-Tonbridge services to use platform 3 would help.
 
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While I can’t really oppose the junctions around Lewisham, can I add Balham Junction (country end) and the various junctions at Streatham and Streatham Common. There are plans for Selhurst so sorting out Balham and Streatham Common would sort out most of the slow line issues out of Victoria. Fast line issues would need a seriously big load of digging at Clapham Junction to get trains over from the fast line to the West London Line.
 

Peregrine 4903

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While I can’t really oppose the junctions around Lewisham, can I add Balham Junction (country end) and the various junctions at Streatham and Streatham Common. There are plans for Selhurst so sorting out Balham and Streatham Common would sort out most of the slow line issues out of Victoria. Fast line issues would need a seriously big load of digging at Clapham Junction to get trains over from the fast line to the West London Line.
I was going to mention the Balham and all of the Streatham Junction issues as well.

Once you've solved Windmill Bridge there are not fast line issues on the BML between Victoria and East Croydon with the exception of London Victoria itself and Battersea Pier Junction, plus Pouparts Junction and the Fast Reversible but there is utterly no point in solving these.
 
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