Which junctions would you grade-separate?

[The Planner]

For this one, you could fairly easily remove a lot of the issues by splitting the Nuneaton-Leamington services at Coventry. I doubt there's a huge demand for through traffic, and if there was a lot of demand, you could time the Leamington-Coventry and Coventry-Nuneaton services to give reasonable connections. Yes I know that's not as ideal for passengers but it would save an awful lot of money.

I would also hazard a guess that the lack of 4-tracking between Birmingham and Coventry is a much bigger barrier to providing more services than the lack of grade separation at Coventry.

Agree with you that double-tracking Coventry-Leamington really ought to be a priority.

That makes Coventry worse as you now have two services sitting taking half the platforms up. 4 tracking is being done, as often noted, its HS2. 4 tracking Coventry to New St doesnt solce capacity at New St itself, or Coventry.

 

[Meerkat]

The 5th track proposal was never going to happen.

And yes, the answer for Woking is zero, unless ETCS & ATO comes along.

Needed for Heathrow South Link isn’t it, which is absolutely essential if they expand Heathrow.
Also allow the stoppers to go to Guildford which would improve many local journeys (see a lot of people changing and running the miles down the island to get to P3!)
AIUI at some point relatively soon the 11 track underbridge just south of the station will need replacing, which might be the moment to do the flyover too (may need to coincide with local developments to find enough work and lay down space).

Back to Northallerton, I think the biggest issue here is that developments have extended right up to track boundaries, so killing any hopes of simple improvements. Obviously the worst culprits are Northbound services heading for Yarm, as these generally call at Northallerton, blocking the northbound main line, then cross the southbound after they leave the station. If the northbound platform on what is now the freight line had been retained then northbound services to Yarm could have used it, and there would be no conflicts. But the level crossings on this route become a problem as well.

Isn’t there still space to build new ECML platforms on the west side and then make the current ones for the Middlesbrough line, with a new flyover/under to the south?

When my crayons get drunk they go really big at Newark. Build a whole new 2 level station the other side of the main road to the current one. Gets rid of the crossing and creates proper connections for ECML to Nottingham and Lincoln. Transformational as the slide deck would say!

 

[Nottingham59]

In a fantasy world, I'd vote for Blackfriars Junction.
It's a huge constraint to have a flat junction so close to the Thameslink core.

 

[DynamicSpirit]

In a fantasy world, I'd vote for Blackfriars Junction.
It's a huge constraint to have a flat junction so close to the Thameslink core.

While I think that is true, the problem there is more from the decision to run the Wimbledon trains right through the core instead of terminating them at Blackfriars. My understanding is that that was a political decision. Recast the timetable so most of the trains from Elephant and Castle terminate at Blackfriars, and everything from London Bridge runs right through the core, and then the flat junction becomes a non-issue.

My only doubt about that is that I'm not sure what the capacity of the two terminating platforms at Blackfriars is. In an ideal World, it would be good to have trains heading down towards Elephant and Castle, with an additional stop at Camberwell, something like every 5 minutes. But I'm not sure if that's too much for the terminating platforms to cope with.

 

[Big Jumby 74]

AIUI at some point relatively soon the 11 track underbridge just south of the station will need replacing

A joint NR/Woking BC project, all now on hold/kicked in to the long grass last I heard, due to un-resolvable access issue (proposed dropping of main road level for new bridge structure?) to down yard for HGV's (initially) and more recently, the financial melt down of Woking BC, leaving the current bottleneck under the bridge to carry on for how long (ever?) and a pile of rubble resulting from early compulsory demolitions now forming a long term 'rubble feature' just south of the bridge! Nothing's going to change anytime soon.

 

[Bald Rick]

Needed for Heathrow South Link isn’t it,

Yes, but wasn’t in the HSL plans. They assumed it would have been built.

which is absolutely essential if they expand Heathrow.

Heathrow don’t think so.

While I think that is true, the problem there is more from the decision to run the Wimbledon trains right through the core instead of terminating them at Blackfriars. My understanding is that that was a political decision.

It was. Albeit based on consultation responses which had a lot of support for retaining Sutton loop through the core. However, that was just a straight swap for services coming from Denmark Hill - there would still have been a maximum of 16 tph coming via London Bridge into the Thamelsink core.

My only doubt about that is that I'm not sure what the capacity of the two terminating platforms at Blackfriars is. In an ideal World, it would be good to have trains heading down towards Elephant and Castle, with an additional stop at Camberwell, something like every 5 minutes. But I'm not sure if that's too much for the terminating platforms to cope with.

It could do 10, possibly 12 trains an hour of the 2 platfroms. More than the capacity of the rest of the network to get them there.

A joint NR/Woking BC project, all now on hold/kicked in to the long grass last I heard, due to un-resolvable access issue (proposed dropping of main road level for new bridge structure?) to down yard for HGV's (initially) and more recently, the financial melt down of Woking BC, leaving the current bottleneck under the bridge to carry on for how long (ever?) and a pile of rubble resulting from early compulsory demolitions now forming a long term 'rubble feature' just south of the bridge! Nothing's going to change anytime soon.

The former leader of Woking BC was quite the character.

 

[The Ham]

Heathrow don’t think so.

They want to have 50% more aircraft (presumably a similar uplift in passengers) and they don't think a rail link is needed.

That's fine of course, everyone knows how much capacity there is on the local road network....

Arguably a lot of passengers could fly in/out and bit have to use local travel - however that's not necessarily true for staff (aircraft based staff it might work for, but not other staff).

 

[Meerkat]

A joint NR/Woking BC project, all now on hold/kicked in to the long grass last I heard, due to un-resolvable access issue (proposed dropping of main road level for new bridge structure?) to down yard for HGV's (initially) and more recently, the financial melt down of Woking BC, leaving the current bottleneck under the bridge to carry on for how long (ever?) and a pile of rubble resulting from early compulsory demolitions now forming a long term 'rubble feature' just south of the bridge! Nothing's going to change anytime soon.

The access issue was due to councillors folding for NIMBYs and a bit of a side issue. The bridge was heading £90m+ over budget and going to cause ludicrous disruption. Its really needed but nobody is going to fund that much, nor put up with it being closed for that long.

The former leader of Woking BC was quite the character.

Did you deal with him? A bullying egotistical megalomaniac lucky not to have got publicly lynched! Did massively improve the town centre though.....

 

[MontyP]

Yes, it hadn't occurred to me that the crossings were timed to be the same, because although I've been over the crossing many times and I always pay attention at the flat crossing, strangely I don't ever remember seeing a service passing in the other direction at that point!

Maybe I'm always on the wrong side of the train (I do tend to sit on the left on those services).

I suppose I'd guess each pair of passenger services would need a 2-3 minute slot and the freight maybe 3-4? So that would mean a total of somewhere between 7 and 10 minutes an hour when the ECML section was blocked?

So basically (as a novice when it comes to train planning) grade separation is not necessary on a basic 2-track junction, as the crossing moves can always be (in theory) timetabled to be at the same time?

Simplistically if a junction exists from origin A to destinations B and C, then it should always be timetabled so that A-B and B-A cross the junction at the same time, similarly A-C and C-A?

All very well but this assumes no further constraints up or down the line, and obviously if one service is delayed then it messes up the sequencing at the junction. For this reason I'd imagine that separation of Micklefield junction would be highly desirable.

Why did the GWR think that Cogload Junction (probably one of the earliest grade-separated junctions on exclusively 2-track routes) was necessary? Just for operational flexibility?

 

[Zomboid]

I think grade separation is always preferable as that removes any constraints caused by a flat crossing.
It's not always worth the expense or possible in the available space, but in a money's no object ideal world then every junction would be grade separated.
Cogload Junction was built for two 2 tracks into 4 - the same kind of thing as Worting Junction, so a down train from Bristol could arrive and head to Taunton without conflicting with any of the other possible routes.

 

[43074]

ETCS will siml,y enable the timetable to run tuthfully, rather than with the fiddles in place today to make it look like it works.

Which "fiddles" are those, out of interest?

And have they been designed out of the timetable in December '25, noting that some of the long distance paths have/(had) as much as (5) pathing time approaching Woolmer Green to follow fast Thameslink services in an arrangement less optimal than the current timetable?

 

[Bald Rick]

Did you deal with him?

Met him a few times, yes.

Which "fiddles" are those, out of interest?

Various chunks of pathing and performance time, plus margins that don‘t quite work in some cases.

And have they been designed out of the timetable in December '25

It’s not been finished, yet!

 

[61653 HTAFC]

Serious suggestion: Woking.

Tongue-in-cheek suggestion: Springwood junction just west of Huddersfield station (where the line to Barnsley leaves the main line to Manchester) just because it would be interesting to see how you'd achieve it in such a tight space.

 

[zwk500]

So basically (as a novice when it comes to train planning) grade separation is not necessary on a basic 2-track junction, as the crossing moves can always be (in theory) timetabled to be at the same time?

With no other constraints, yes. However, if junctions aren't the right travel time apart you have to pick one to optimise and the other ends up needing schedules having additional time put in to avoid conflicts.
Also if a junction is used by long trains, has a fast main route, or has a big speed difference between the main route and the branch, even with pairing of the routes the impact of the conflicting move on line capacity may be too great.