Which Tube lines can "platform and hold" all the trains in service?

[Kristofferson]

Watching an old episode of The Tube on London Live the other week, there was mention of an interesting fact: There are more trains in service on the Victoria Line at any time, than there are stations on the line. This means that during disruption, some trains are held at red signals (or the ATO equivalent!) in tunnels - which obviously isn't ideal for passengers trying to get somewhere.

This led me to wonder... Which Tube lines have the capacity to hold all the trains currently in service at platforms during disruption? And how do they stop trains stacking up in tunnels on lines which don't have the capacity?

 

[yorkie]

This led me to wonder... Which Tube lines have the capacity to hold all the trains currently in service at platforms during disruption?

Can you clarify if you are asking for:
- All LU lines (some of which are tube, some are sub-surface)?
- All LU deep level tube lines?
- All sections of line which are in deep level tubes?

And how do they stop trains stacking up in tunnels on lines which don't have the capacity?

If they don't have the spare capacity, I don't really see how you can prevent it.

 

[Domh245]

Watching an old episode of The Tube on London Live the other week, there was mention of an interesting fact: There are more trains in service on the Victoria Line at any time, than there are stations on the line. This means that during disruption, some trains are held at red signals (or the ATO equivalent!) in tunnels - which obviously isn't ideal for passengers trying to get somewhere.

This led me to wonder... Which Tube lines have the capacity to hold all the trains currently in service at platforms during disruption? And how do they stop trains stacking up in tunnels on lines which don't have the capacity?

I don't think that there are any lines where there are more platforms than trains, other than the W&C on a saturday - on weekdays there are 5 trains and 4 platforms! I think the bakerloo might be close to having a similar number of trains and platforms?

 

[jopsuk]

Bakerloo has 25 stations each with two platforms- 50 platforms. As far as I can tell it has 33 Mark 2 1972TS?

 

[ECML180]

If they don't have the spare capacity, I don't really see how you can prevent it.

Empty trains in a platform then continue into a tunnel/siding empty, leaving trains with passengers to wait in platforms? Can't see much benefit though unless a full scale evacuation was required.

 

[Daniel]

If a line is blocked either for a prolonged period or a shorter but still significant period, then the train service will be reversed/diverted/reformed as required to maintain a service to other areas of the line. If this is not possible owing to a lack of reversing points, other avenues can be explored, for example, de-training a service and pushing it empty into the tunnel to get stuck, to allow a service train to enter the platform behind it. If a shutdown occurs for a significant period, controllers will aim to have trains stuck in tunnels detrained within 1 hour. Detrainment in this case does not necessarily mean train to train or train to track - there are other resolutions such as getting the nose of a train into the rear of an occupied platform and detraining through the cab.

As to the original question, for pure trains vs platforms, I would imagine the only two lines with more of the former would be the Victoria and Waterloo & City - though you would probably find that if a situation developed where a whole line needed to be held, with the exception for one where it is unsafe to move trains, some trains would already have been cancelled and put to depot.

 

[Kristofferson]

Interesting stuff - as I thought, the general rule is more platforms than trains on most LU lines (I did mean all LU lines - apologies I wasn't clear enough).

It's also interesting to know the plans for detraining on lines with more trains than platforms.

 

[Busaholic]

If the recent announcement of up to 50 new,additional trains for the Northern Line comes to fruition, even allowing for two new stations there will certainly be more trains than platforms

 

[edwin_m]

On some lines the signalling is designed to minimise the number of trains between stations or between evacuation shafts, so that if an evacuation is necessary each evacuation point only has one train to deal with.

This is particularly important with moving block systems which are capable of bringing a train very close behind another one. So unless control reacts promptly a stopped train could have several others stacked up behind within a few minutes. I don't know what happens on the Underground but I would have thought it was a particular worry on the Tube lines (except Jubilee line extension) where evacuation is through the train and out of the end door onto the track.

 

[hassaanhc]

On some lines the signalling is designed to minimise the number of trains between stations or between evacuation shafts, so that if an evacuation is necessary each evacuation point only has one train to deal with.

This is particularly important with moving block systems which are capable of bringing a train very close behind another one. So unless control reacts promptly a stopped train could have several others stacked up behind within a few minutes. I don't know what happens on the Underground but I would have thought it was a particular worry on the Tube lines (except Jubilee line extension) where evacuation is through the train and out of the end door onto the track.

I was on an eastbound Jubilee Line train last year, that was asked to hold by cobtrol at Canary Wharf then North Greenwich for 2-3 minutes each, due to a train fault at Green Park westbound. However this was off-peak.

 

[Daniel]

The basic rule for incident management (from a line controllers perspective) on LU: "Regulate ahead, hold behind, call the cavalry".

 

[Mutant Lemming]

What about the stretches from Great Portland Street to Aldgate and Tower Hill to Edgware Road ? Intertwined Met and C,H & C and then intertwined DR and C,H & C ?

 

[Daniel]

What about the stretches from Great Portland Street to Aldgate and Tower Hill to Edgware Road ? Intertwined Met and C,H & C and then intertwined DR and C,H & C ?

What do you mean? If you mean about holding trains on different lines, a section of track is controlled by a specific line controller, so all trains in that section follow his/her instructions. The north side of the circle, for example, is controlled by the Metropolitan Line controller.

 

[Mutant Lemming]

What do you mean? If you mean about holding trains on different lines, a section of track is controlled by a specific line controller, so all trains in that section follow his/her instructions. The north side of the circle, for example, is controlled by the Metropolitan Line controller.

They may be controlled by the relevant lines but the trains running over those metals are as mixed as they are on the map. So if the original poster wants to know how many trains of a specific line can be held on that line as per the map then over those stretches what trains are you going to have in the platforms ?

 

[Nym]

Watching an old episode of The Tube on London Live the other week, there was mention of an interesting fact: There are more trains in service on the Victoria Line at any time, than there are stations on the line. This means that during disruption, some trains are held at red signals (or the ATO equivalent!) in tunnels - which obviously isn't ideal for passengers trying to get somewhere.

This led me to wonder... Which Tube lines have the capacity to hold all the trains currently in service at platforms during disruption? And how do they stop trains stacking up in tunnels on lines which don't have the capacity?

Small point to note, the Victoria Line does have red signals, and restrictive aspects on the Block Marker Boards.

Not many lines actually have more trains than platforms, and as has already been said, you can detrain into sidings and/or depots. One problem for the Victoria Line is that there is only one significant stabling area, whenever there is an issue, four trains will almost certainly be pulled at Brixton and Walthamstow, using the over-run tunnels.

 

[Daniel]

They may be controlled by the relevant lines but the trains running over those metals are as mixed as they are on the map. So if the original poster wants to know how many trains of a specific line can be held on that line as per the map then over those stretches what trains are you going to have in the platforms ?

Ah, sorry, mistook your question slightly.

In short, it's a complex question which varies by line and location.

In practice on the shared sections, all trains coming under one controller mean that from a service control point of view, the differences in the train's line aren't really recognised; they simply see trains under their control with a different destination. I take your point that you have many trains in that area, and inevitably if there is an incident you will not be able to 'platform and hold' between Aldgate and Baker Street. The ease of a small incident here causing extended delays elsewhere is evident through trains being de-trained on the Metropolitan Line at Harrow-on-the-Hill within 2-3 minutes of a shutdown in the city, in order to reduce congestion.

 

[Kristofferson]

Glad to see the conversation on this thread, thanks for the input so far all

 

[Mutant Lemming]

Small point to note, the Victoria Line does have red signals, and restrictive aspects on the Block Marker Boards.

Not many lines actually have more trains than platforms, and as has already been said, you can detrain into sidings and/or depots. One problem for the Victoria Line is that there is only one significant stabling area, whenever there is an issue, four trains will almost certainly be pulled at Brixton and Walthamstow, using the over-run tunnels.

..and can someone remind us why any 09 stock transfers have to be done by road ?

 

[Daniel]

..and can someone remind us why any 09 stock transfers have to be done by road ?

Because they're too wide to fit into the Piccadilly line tunnels.

 

[Met Driver]

I was recently informed that they can physically fit down the Picc tunnels throughout between Finsbury Park & Barons Court, albeit they are a bit too close for comfort in some areas and thus do not conform to modern day tolerances.