Why do Morden trains run via Bank?

[Sprigibax]

Of course The Charing Cross branch now serves Battersea, but before that, does anyone know the reason why Morden trains run via Bank instead of Charing Cross? Charing Cross is the more direct and faster route, so surely that would make more sense for through journeys?

 

[PeterC]

Where do you turn the Bank trains?

 

[Sprigibax]

Kennington, instead of the Charing Cross ones?

 

[Peter Mugridge]

Kennington, instead of the Charing Cross ones?

They come in a different tunnel that can't access the Kennington Loop...

 

[stuu]

The demand historically was much higher to the Bank branch, especially in the peak, which is presumably why there was never a connection to the loop

 

[Basil Jet]

Kennington, instead of the Charing Cross ones?

While Bank branch trains can reverse via Kennington Siding (not the loop), this requires they share track with trains from Charing Cross to Morden to get into the siding, and then share track with trains from Morden to Charing Cross to get out. See either of the two diagrams at the top of http://tubenoise.com/how.html (both of which predate the construction of the Battersea branch, but are correct in the salient points). So low frequency service with Bank Kennington terminators would be okay, for instance if the Night Tube opened on the Bank Branch, but for frequent daytime service the current pattern is a lot easier to timetable and run.

 

[JonathanH]

The demand historically was much higher to the Bank branch, especially in the peak, which is presumably why there was never a connection to the loop

There could only be a connection to the loop if there was a junction between the Bank branch and Charing Cross branch north of Kennington. Bank trains can access a reversing siding south of the Kennington platforms, but that can also be accessed by the Charing Cross branch trains.

As the Charing Cross platforms are on the outside, there would always be a conflict if Bank trains were to terminate at Kennington and Charing Cross trains go through to Morden.

All shown here - http://tubenoise.com/how.html

How It Works
TubeNoise is an attempt to show the real-time position of tube trains on the Northern Line around Kennington. This is a somewhat complicated area of the tube network due to the joining up of the Charing Cross and Bank branches of the Northern Line at Kennington.

Around half of the trains are turned around at Kennington on the Kennington loop - which allows Southbound Charing Cross trains to turn around and head North. There is also a siding at Kennington that allows Southbound trains from either branch of the line to return North on either branch of the line.

Charing Cross is the more direct and faster route, so surely that would make more sense for through journeys?

Is the concept of faster through journeys relevant? Most use of the underground will involve a journey ending in central London. Euston is marginally quicker changing at Stockwell rather than Kennington.

 

[DanNCL]

It ultimately stems back to when and how the different sections of the Northern line were built.

The Northern line was originally two separate unconnected lines. One was the City & South London Railway, this went from Clapham Common to Euston via Bank. The other was the Charing Cross, Euston and Hampstead Railway, which ran from Embankment to both Golders Green and Highgate.

In the 1920s the two railways were integrated into what is now the Northern line. The first phase of that was to extend the City & South London Railway from Euston to just south of Camden Town, this created the complex junction that’s there today and resulted in direct trains from both Edgware (which opened at the same time) and Highgate to both Embankment and Clapham Common.
The next phase was to extend southwards from Embankment to Kennington. It should be noted that this coincided with the extension south from Clapham Common to Morden. Though through trains were planned and did operate from the Charing Cross branch to Morden, there was neither the capacity nor demand for every train from both branches to do so. As such, the extension to Kennington from Embankment saw the loop constructed to turn back trains from the Charing Cross branch. The service pattern therefore became Edgware and Highgate - Morden via Bank, and Edgware and Highgate - Kennington via Charing Cross, with some trains doing Edgware or Highgate - Morden via Charing Cross.

The next change to the Northern line was the extension to High Barnet and Mill Hill East but this had no impact on what happened at Kennington.

Fast forward to recent years and we have the Battersea extension. This was connected at Kennington to Charing Cross branch because most trains from the Charing Cross branch terminated at Kennington which meant that the Battersea extension could run without reducing service to Morden. There was no technical reason why the Battersea extension couldn’t have been connected to the Bank branch, but ultimately the decision was made to tunnel and connect it to only the Charing Cross branch.

Hope this explains how the Northern line ended up how it is today, and why it’s predominantly Bank branch trains that run to Morden.

 

[JonathanH]

There was no technical reason why the Battersea extension couldn’t have been connected to the Bank branch, but ultimately the decision was made to tunnel and connect it to only the Charing Cross branch.

One obvious technical reason is that the junctions to Battersea were constructed off the loop, rather than on the plain line South of Kennington. If they had been built south of Kennington, then trains to Morden from the Charing Cross line would have had to conflict with trains to Battersea from the Bank line. The only way round that would be tunnels off the loop to a point South of the Battersea junction, which sounds somewhat complex.

 

[stadler]

Where do you turn the Bank trains?

They come in a different tunnel that can't access the Kennington Loop...

Kennington also has a turnback siding for the Bank branch trains which can be used.

 

[Magdalia]

Forty something years ago I briefly lived in the borderlands of the People's Republic of Tooting, and used the southern end of the Northern Line. In those days there was no such thing as a public timetable for the Northern Line so I started an attempt to work it out for myself. I still have a little notebook of observations, mainly taken at Clapham Common, where it was possible to see the trains in both directions. The observations are difficult to decipher now, and the project was never completed because I quickly moved on to other dodgy parts of South London.

My impression from the notebook, and what I remember, is that the off peak service was relatively simple, with alternate Morden-Mill Hill East and Morden-Colindale via Bank. The Charing Cross branch was alternately Kennington-High Barnet or Kennington-Edgware. Off peak there were no through trains from Morden to either High Barnet or Edgware, or on/off the Charing Cross branch.

But I never established the peak pattern to my satisfaction, maybe there wasn't one! Most trains via Bank were end to end Morden-High Barnet or Morden-Edgware, trains via Bank to/from Mill Hill East disappeared in the peak. There was a further complication with some Bank branch trains terminating/starting at Tooting Broadway. I couldn't see the point of this, apart from providing Citizen Smith and the Tooting Popular Front with seats, which would have made it more difficult to shout "Power to the People".

In the peak some of the Charing Cross branch trains ran through to/from Morden, but nearly all of these were alternate High Barnet and Mill Hill East trains. Morden-Edgware via Charing Cross was only a few trains in the shoulders of the peak, but there were Kennington-Edgware trains via Charing Cross in the peaks. At the end of the peak there would also be northbound trains terminating at Hampstead and Finchley Central, and I guess that southbound trains started from those at the start of the peaks.

Having preserved the notebook for more than 40 years, this is probably going to be my best opportunity to share what it contains!

 

[Dstock7080]

Kennington also has a turnback siding for the Bank branch trains which can be used.

A single siding to cope with a 2½min peak service?

 

[daodao]

Forty something years ago I briefly lived in the borderlands of the People's Republic of Tooting, and used the southern end of the Northern Line. In those days there was no such thing as a public timetable for the Northern Line so I started an attempt to work it out for myself. I still have a little notebook of observations, mainly taken at Clapham Common, where it was possible to see the trains in both directions. The observations are difficult to decipher now, and the project was never completed because I quickly moved on to other dodgy parts of South London.

My impression from the notebook, and what I remember, is that the off peak service was relatively simple, with alternate Morden-Mill Hill East and Morden-Colindale via Bank. The Charing Cross branch was alternately Kennington-High Barnet or Kennington-Edgware. Off peak there were no through trains from Morden to either High Barnet or Edgware, or on/off the Charing Cross branch.

But I never established the peak pattern to my satisfaction, maybe there wasn't one! Most trains via Bank were end to end Morden-High Barnet or Morden-Edgware, trains via Bank to/from Mill Hill East disappeared in the peak. There was a further complication with some Bank branch trains terminating/starting at Tooting Broadway. I couldn't see the point of this, apart from providing Citizen Smith and the Tooting Popular Front with seats, which would have made it more difficult to shout "Power to the People".

In the peak some of the Charing Cross branch trains ran through to/from Morden, but nearly all of these were alternate High Barnet and Mill Hill East trains. Morden-Edgware via Charing Cross was only a few trains in the shoulders of the peak, but there were Kennington-Edgware trains via Charing Cross in the peaks. At the end of the peak there would also be northbound trains terminating at Hampstead and Finchley Central, and I guess that southbound trains started from those at the start of the peaks.

Having preserved the notebook for more than 40 years, this is probably going to be my best opportunity to share what it contains!

I also lived near Tooting Broadway from 1982-4 and used the Northern line primarily to access the West End. I always needed to change at Kennington outside Mon-Fri peak hours. I did once make an evening journey to Woodside Park and back, and recall travelling via Bank (a route that otherwise I rarely used), but can't remember whether I needed to change at some point.

 

[ThameslinkUser]

A single siding to cope with a 2½min peak service?

Exceedingly different circumstances but the DLR at Bank handles that.

 

[JonathanH]

Exceedingly different circumstances but the DLR at Bank handles that.

It doesn't need to share the relevant points with another route though.

 

[DanNCL]

Exceedingly different circumstances but the DLR at Bank handles that.

That’s only possible because the DLR doesn’t have to wait for the driver to change ends, it can come out of the the turn back siding almost as soon as it arrives.

 

[announcements]

At the end of the peak there would also be northbound trains terminating at Hampstead and Finchley Central, and I guess that southbound trains started from those at the start of the peaks.

These days I think the end-of peak northbounds terminate at East Finchley rather than Finchley Central, however you do get many Finchley Centrals within the peak period in any case. Similarly, Golders Green is used these days, not Hampstead; I've only ever seen Hampstead terminators during planned engineering works, as it requires an awkward change of ends in the running tunnel to traverse the crossover.

Separately, if the Northern line were to split, I have noticed some fantasy maps show Edgware to Battersea and High Barnet to Modern, presumably the easy visual option given how they are arranged on the tube map. However, I'd have thought it would make more sense to have them the other way around, particularly as High Barnet to Kennington can be (and has done on previous versions) be represented as one straight vertical line on the tube map. Plus, geographically, the Bank branch tunnels are to the left of Mornington Crescent, not the right - contrary to how it is depicted on the tube map.

 

[Ken H]

When they built 'standard' stock it had A and B ends. You could only couple an A end to a B end. So they needed to keep the trains all the same way round. *
I think the 1938 stock was the last tube stock to have that restriction.
But the Kennington loop saw little use till the coupling restrictions went with new stock.

Is Kennington the only loop on the Underground?

* Later the designation was changed to A and D ends. The axles were call A B C and D and the ends were named after the nearest axle.

 

[swt_passenger]

Separately, if the Northern line were to split, I have noticed some fantasy maps show Edgware to Battersea and High Barnet to Modern, presumably the easy visual option given how they are arranged on the tube map. However, I'd have thought it would make more sense to have them the other way around, particularly as High Barnet to Kennington can be (and has done on previous versions) be represented as one straight vertical line on the tube map. Plus, geographically, the Bank branch tunnels are to the left of Mornington Crescent, not the right - contrary to how it is depicted on the tube map.

If the line was completely split the decision would presumably have to be made on the basis of a depot for each line, so doesn't end up as Morden-High Barnet and Battersea-Edgware by default?

 

[Mojo]

Is Kennington the only loop on the Underground?

Hainault, Terminal 4, Inner Circle line…
Plus of course trains can also end up the “wrong way” round by going via the triangular junctions at Earls Ct, Aldgate, Watford.

 

[announcements]

If the line was completely split the decision would presumably have to be made on the basis of a depot for each line, so doesn't end up as Morden-High Barnet and Battersea-Edgware by default?

Good point!

 

[stuu]

If the line was completely split the decision would presumably have to be made on the basis of a depot for each line, so doesn't end up as Morden-High Barnet and Battersea-Edgware by default?

I believe depots is a problem if it were split, as there are three, and whichever way it is split one side ends up with two depots and the other with only one which isn't enough, so it couldn't actually be fully split without extra space being found

 

[bluegoblin7]

There are only two depots on the Northern line - Golders Green and Morden. All other locations are classed as sidings.

However, this problem is frequently overstated - any Northern line split would likely be in name only, much the same as the Circle and Hammersmith & City lines are operationally the same thing. Line control would remain combined at Highgate, and it’s highly likely that train crew would remain qualified on all roads. Trains can easily be scheduled to start or finish at the ‘wrong’ depot, as per the SSL (C&H trains can start or stop at any of Neasden, Ealing Common and Upminster).

 

[cle]

Stockwell handles the west end demand perfectly, although yes there are obvious physical reasons why not. So both WE and City are well catered for.

Stockwell / Vic line is also why a NLE taking on all Charing Cross routes would be perfectly fine.

 

[ThameslinkUser]

That’s only possible because the DLR doesn’t have to wait for the driver to change ends,

Hence "exceedingly different circumstances". Not sure what else I could be referring to.

 

[DanNCL]

Hence "exceedingly different circumstances". Not sure what else I could be referring to.

Every train terminating there and there not being other conflicting workings too.

 

[ThameslinkUser]

They're not "exceedingly different". That's just different.

 

[Daniel]

These days I think the end-of peak northbounds terminate at East Finchley rather than Finchley Central

Whilst you may have mean Southbound, which is more common late at night, no train is scheduled to terminate at East Finchley Northbound. In order to get into Highgate sidings they'd either have to shunt via the main line and block the Northbound, or head up to Finchley Central anyway. They're booked to terminate in Finchley platform 1 as Mill Hill and Barnet trains can run around via platform 2.

 

[announcements]

I could have sworn I have seen East Finchley terminators during the morning peak from central London locations. Unless I were seeing things, is it possible that the train might have been terminating there as an exception rather than the rule? In the same way trains might terminate at Wood Green on the Picc line even if not originally timetabled to do so.

 

[Daniel]

I could have sworn I have seen East Finchley terminators during the morning peak from central London locations. Unless I were seeing things, is it possible that the train might have been terminating there as an exception rather than the rule? In the same way trains might terminate at Wood Green on the Picc line even if not originally timetabled to do so.

No, unless the line was suspended North of East Finchley. The only place a train can go from East Finchley Northbound is onwards to Finchley Central, or reversing via the main line meaning no other service could proceed until the driver had changed ends. A train would not be reversed North to South at East Finchley for late running when services are still continuing Northbound - it's generally quicker to just carry on to Mill Hill anyway. You will, however, have seen Finchley Central terminators from London in the peak.