Train bunching and line splitting

[marbles]

As a passenger on the Northern Line I've often wondered about a couple of things.

1) Why is the Northern Line so prone to bunching of trains? I can't tell you the number of times I've been at Mornington Crescent, waiting for a southbound train, to have the next three trains show on the indicator as arriving in something like 7mins, 8mins and 9mins. Why don't they get spaced out more?

2) I know Camden Town is a nightmare from a signalling point of view, but is there a reason why the line can't be split into a Kennington/Charing Cross/Edgware line and a Morden/Bank/High Barnet line, forcing people to change at Camden if they need the other line, as that would seem to ease the chaos of filtering the trains for the different branches at Camden now.

[jamesb]

I read in the Metro that they are considering 2) or maybe it is even planned to happen?

I guess one problem would be congestion at Camden Town, and whether or not Camden Town could cope with herds of passengers moving between platforms in the rush hour... If this lead to Camden getting frequently closed because of overcrowding, it might become very frustrating for passengers. But I guess you could change at Euston as an alternative, although it would be a bit of walk.

[Deleted]

The main problem, as James has said, is Camden's lack of capacity for interchanging passengers. LU can't redevelop Camden at the moment as planning was refused (I believe). If Camden were to be redeveloped I expect that they would change the junctions to be more efficient.

To think almost a century ago people were marvelling at the all of the non-conflicting movements at Camden!

[Deleted]

As the others have said, Tfl are planning this; a split and a signal upgrade would allow 30tph on each branch. But Camden Town, and to a lesser degree Kennington, would have to be redeveloped. Camden Town's redevelopment plan are causing a lot of controversy because certain buildings and part of the market would have to be knocked down, but everyone agrees that something must happen.

They already ran that way for a short period in 2003, after a train derailment at Camden Town, when there was engineering works on the junctions.

[cetacean]

Even the fanciest junction requires trains to slow down where the flows merge, and once resignalled it'll be the weak point of the whole service, so the official plan is full segregation.

The planning permission rejection of Camden Town was a long time ago now. I presume any new scheme won't be announced until the resignalling requires it, so they have a stronger case.

[Deleted]

rob said:

If Camden were to be redeveloped I expect that they would change the junctions to be more efficient.

I don't think there are any plans to rebuild the junction. The cost/benefit would not be worth it, and all the movement are non-conflicting anyway. The new signalling, better service control, and improved train performance should increase the junction capacity a bit, but as mentioned the ultimate plans are to split the line anyway.

[tubeprune]

marbles said:

As a passenger on the Northern Line I've often wondered about a couple of things.

2) I know Camden Town is a nightmare from a signalling point of view, but is there a reason why the line can't be split into a Kennington/Charing Cross/Edgware line and a Morden/Bank/High Barnet line, forcing people to change at Camden if they need the other line, as that would seem to ease the chaos of filtering the trains for the different branches at Camden now.

I tried to get this done in the early 1980s with '59 Stock working Morden to High Barnet and '72s doing Kennington - Edgwares. The fleet sizes were just right to give about 30 tph on each branch rather than the 20 tph they get now. The Camden interchange problem killed it, even though there were a lot less passengers then. AIUI, they are looking at it again.

[Ben]

If Camden Town were redesigned for improved passenger flow it wouldnt necesarily need to be split into two lines, since operators could make better use of a first-come-first-serve arrangement, with all trains from points south marked as 'Camden' till that point.

[tubenetwork]

Hi all

Putting it bluntly though not ignorant to the issues, i don't really understand why a descent level of service cannot be obtained through the signal upgrade while keeping the line as it is. I do not think splitting the line is as simple and would give the benefits some think

As a driver i do fully understand the frustrations of waiting just outside Camden whilst one or two trains are routed in front of me. But this is mainly to do with the decisions of the controller or machine and not to do with any issues re the junction. Also there are so many trains that can be pushed through any one of the platforms at Camden within any hour taking in consideration dwell times and the crowds!

As most of us know the junction was re-built to allow certain non conflicting movements and i feel it is an engineering marvel.

There were levels of service way before now that were much higher on all branches and the line coped. So why not now? I suppose i could answer my own question as the signaling was reconstructed a bit, reducing line capacity in the 80's following large passenger and service decline thus reducing maintenance.

One of the main advantages of now is that there is flexibility, which if used correctly can be used to over come gaps in the service and shut downs.

If the line were split would this flexibility be kept for emergencies such as shut downs, large gaps in the service or would a whole section of line be shut down? For example: security alert Chalk farm. Would the charing cross branch be completely shut down or would edgware trains be allowed to venture via barnet to keep some sort of service going? And visa versa for everything else.

I would favour some sort of service.

It amazes me that we are supposed to be living in an advanced age with many technologies to help us along but we can not deliver a descent service now where as this did happen in the 20's 30's etc.

One day i feel the powers at be will have to face up that eveything the cheaper has been done and the only answer would be to extend platforms and trains as was done previously to answer the same problem of increasing capacity. Serious money and ideas will solve the issue.

[Deleted]

Of course I'm all for keeping those possibilities in situations when it's needed, just like it should be possible for the District and Piccadilly or Met and Jub to use each other's tracks in the parallel sections, for example. But as Tfl says in their Transport 2025 document that it is not possible to reach that 30 tph with the branches the way they are now.

[mandgc]

In Marbles' original complaint- the fact that the next three trains will arrive in 7, 8 and 9 minutes suggests that the first train had been delayed ELSEWHERE and was holding back the second and third trains. The fault is not at Camden Town which is almost foolproof in allowing arriving trains to take their proper route with as little delay to other trains as possible.
Delays such as this can only be dealt with either by having Standby Trains (at Golders Green or Archway for instance ) or better supervision of the train service by the Supervisors

[Ben]

I tried working out the frequencies and to be honnest from what I can tell it still works at 30tph. But then I realised thats assuming a strict 2min inteval. Seeing as a train might be held up for more than a minute at any given station, it falls to pot if there are delays. Surely it would work with a computer picking the best route at the last possible moment (under ATO)? But then there would have to be decent interchange facilities at Camden. Maybe swap the northbound and southbound for one branch over (so that the 2 northbounds are nearest each other) then dig out everything between them? Maybe thats the plan anyway. But I have to agree with tubenetwork here, the only way forward after a while is longer trains and extra tracks. If WW2 hadn't happend the northern would be running 9cars and have express tracks between Golders and Morden. That would solve the problem at camden at a stroke!

[Deleted]

benedict said:

If Camden Town were redesigned for improved passenger flow it wouldnt necesarily need to be split into two lines, since operators could make better use of a first-come-first-serve arrangement, with all trains from points south marked as 'Camden' till that point.

Are you saying that passengers would just get on a train marked Camden and only when they arrived find out which way it was going?

If so, I honestly can't think of anything worse. Imagine the chaos as passengers realise they suddenly need to get off this train and wait for the next one! Not to mention those who have been hanging around at Camden after being turfed off the train in front. Then add in the passengers who enter the network at Camden.

[Ben]

Work in progress Something needs to be done though; it would be equally bad if people had to change regardless because of a line split. At least my way theres roughly a 50% chance the passengers will be on the right train anyway

[Deleted]

mandgc said:

Delays such as this can only be dealt with either by having Standby Trains (at Golders Green or Archway for instance ) or better supervision of the train service by the Supervisors

Hopefully the new control system will allow for better train regulation to reduce bunching. Some modern control systems also have intelligent junction routing, which routes trains based on a list of selectable priorities (e.g junction arrival time, whether train is on time or late, whether train is scheduled or extra, etc etc).

[Deleted]

benedict said:

If Camden Town were redesigned for improved passenger flow it wouldnt necesarily need to be split into two lines, since operators could make better use of a first-come-first-serve arrangement, with all trains from points south marked as 'Camden' till that point.

Sorry, but that's the most ridiculous thing I've read this week!

The operator must know which branch the train is heading before the junction, as there are issues such as operator relief, train stabling, and correct timetabling on the return journey, which could all be affected if the train visited the other branch. It would also be quite annoying to passengers if they were taking part in a "which branch lottery".

[tubenetwork]

To be honest most of the problems with experienced on the Northern is caused by people rather than infrastructure.

Examples: Trains held outside of Golders green, Edgware, Morden etc. when there is a free platform. I'm aware the route is from the machine roll but human awareness and then intervention to change that route into the free platform would help allot on speeding up the service.

Trains delayed in Camden junction while one or two trains are routed in front of them etc.

There are many examples not only on this line but on others where a little more thought and efficiently, using the existing infrastructure would speed up the service.

I think the main problem is the Morden branch. The rest of the line would operate wonderfully if there were two southern branches or another loop -at say Tooting..Having extra capacity south would allow a more balanced service to operate. Even if it is managed to have a train every 50 seconds on the Morden branch, eventually this wont be enough so were do you go from there?

Again i think eventually a decision would have to be made to extend trains as signaling can only improve to a certain point.

[Deleted]

tubenetwork said:

Even if it is managed to have a train every 50 seconds on the Morden branch, eventually this wont be enough so were do you go from there?

I think you mean every 1min50secs (33tph)?

[marbles]

Thanks for all the replies.

Last year I used to travel home from Camden instead of Morn Cres. I now go from Morn Cres (even though it's a longer walk to the station) because I got fed up with the whole 'indicator says CX but train says Bank' madness which meant I never seemed to be standing on the right platform.

I'd be on a platform with loads of people waiting for a CX train. A Bank train would pull in and pick up no passengers, because all the people waiting for a Bank train were on the other platform watching CX trains go by. It's better to wait at MC after everything gets sorted out.

[Deleted]

I'm so sick of exactly what marbles says here. Yes, it might mean an extra interchange every now and then for some people, but things will be so much easier and clear-cut at Camden Town that I think it's all worth it. Plus the service frequencies that will be going up.

[c5]

I would imagine that if this ever came to be, it would be similar to the Circle & Hammersmith lines, where some trains divert onto the other. This is either when timetable or to cover gaps due to cancellations or service disruption.

I cant imagine say Barnet branch customers would be too happy if they had no trains due to a shut down, and lots of Edgware trains continued to run!

[cetacean]

tubenetwork said:

I think the main problem is the Morden branch. The rest of the line would operate wonderfully if there were two southern branches or another loop -at say Tooting..Having extra capacity south would allow a more balanced service to operate.

I'm confused by this - with most/all CX trains reversing at Kennington, you effectively already have two separate southern branches (the loop and Morden), so there's no capacity-limiting conflicts.

[tubenetwork]

stephenk said:

tubenetwork said:

Even if it is managed to have a train every 50 seconds on the Morden branch, eventually this wont be enough so were do you go from there?

I think you mean every 1min50secs (33tph)?

I just thought of a round about possible figure rather than working out trains per hour as it has been known to have trains pushed through at this rate.

[tubenetwork]

cetacean said:

tubenetwork said:

I think the main problem is the Morden branch. The rest of the line would operate wonderfully if there were two southern branches or another loop -at say Tooting..Having extra capacity south would allow a more balanced service to operate.

I'm confused by this - with most/all CX trains reversing at Kennington, you effectively already have two separate southern branches (the loop and Morden), so there's no capacity-limiting conflicts.

I wouldn't call the kennington/charing cross branch as a second southernly branch equally on par with Morden.

Looking at the line you have Edgware/Barnet, Ch X/Bank. If you imagine a second line to reflect the line to Morden.

[tubenetwork]

c5 said:

I would imagine that if this ever came to be, it would be similar to the Circle & Hammersmith lines, where some trains divert onto the other. This is either when timetable or to cover gaps due to cancellations or service disruption.

I cant imagine say Barnet branch customers would be too happy if they had no trains due to a shut down, and lots of Edgware trains continued to run!

I have lost count how many times i have waited at a very crowded Camden northbound for a barnet branch train only to hear many Edgware's passing through with the dot matrix stuck at 5 mins, actually 10 mins. While even more passengers joining the weekly barnet train waiting party.

[tubenetwork]

What is needed is the linking up of the war shelters along the Morden branch and have a high speed line to morden as planned and talked about many times during the 20's-50's

Put in more reversing facilities and an extra platform at Edgware, Barnet, Morden and double the line to Mill Hill.

Improvement projects that equal national rail, serious commitment and common sense. Less talk and more action. It'll most probably be cheaper than Cross-rail by far..i feel a rant lol.

[cetacean]

tubenetwork said:

Looking at the line you have Edgware/Barnet, Ch X/Bank. If you imagine a second line to reflect the line to Morden.

But I don't get how that would improve capacity on the rest of the line as you suggested, vs sending everything round the Kennington Loop.

tubenetwork said:

Improvement projects that equal national rail, serious commitment and common sense. Less talk and more action. It'll most probably be cheaper than Cross-rail by far..i feel a rant lol.

Sadly no. These days tube lines aren't significantly cheaper than NR lines, but have far less capacity. Crossrail is what you end up with when you try to plan a tube line for best value for money. The economics of building anything as an actual tube line just don't work right now.

[SE13]

Give or take the drivers and rolling stock, why are the two branches not different lines?

Or am I overlooking something glowingly obvious?

[Deleted]

well, because drivers and rolling stock as well as interchanging! A High Barnet - Charing Cross would have no major maintenance depot whilst Golders Green - Morden has both of them.

[mrjrt]

tubenetwork said:

What is needed is the linking up of the war shelters along the Morden branch and have a high speed line to morden as planned and talked about many times during the 20's-50's

Put in more reversing facilities and an extra platform at Edgware, Barnet, Morden and double the line to Mill Hill.

Improvement projects that equal national rail, serious commitment and common sense. Less talk and more action. It'll most probably be cheaper than Cross-rail by far..i feel a rant lol.

Actually, IIRC, the express line was to run to South Wimbledon, and then follow along that alignment out to Chessington or some such, not Morden. That was to run to Sutton.