Why no bi-directional running?

[Deleted]

Does anyone know why bi-directional running has not been adopted with these new signalling schemes on the Jubilee, Victoria and soon to be Northern upgrades?

With systems such as TBTC, one of its normal selling features is this ability, like DLR, where they can implement shuttles, reverse trains that are stuck behind others in a shutdown situation. Not sure about the Vic line signalling, but as it is based on Westrace and radio I can't see why that couldn't do it either.

Is it a cost thing, or basic decision that LU do not want it?

[plasmid]

Probably because it would confuse punters if an Eastbound train arrived on their Westbound platform and vice versa. You know what people with earphones are like...

Reverse running was done on the Victoria Line, I remember as a child their was a problem with the service and we were told to go to the Southbound platform to catch our Northbound train. Can't remember the station, year etc. I'm afraid.

Platform 2 on the Central Line at Leytonstone offers trains in both directions and there are probably a few other stations which do this.

Cost of signs too would be a factor.

[Deleted]

Interestingly on the BART network in California bi-directional working is common, however from my experience it tends to be between stations only.

XF

[castlebar]

Bi-directional running occurs at East Croydon. ("Next stop Brighton" can be the case on two of the usual London bound platforms) It has taught PAX to read the platform indicators before they board - it would be a new skill for some Londoners.

[trc666]

nick0323, I imagine your station would have been Highbury & Islington, Warren Street or Victoria, as south-to-north trains can reverse directly off the platform with passengers at those stations.

[Ben]

It was designed out of the Jubs new signalling at extra expense, allegedly because Tube Lines were not specifically asked for it.

[Deleted]

The Vic Line will be bi-di between sisters and the depot following the last minor closure.

Although it could be done on the passenger carrying routes, I don't think there would be enough crossovers on the passenger carrying routes to make bi-di worthwhile. In most locations it is at least 3-4 stations between crossovers, so if one bound had to be closed between crossovers you would be looking at at least 10 minutes between trains in each direction.

[Deleted]

Isn't bi-di helpful if a train cant move itself under its own power and a train can be summoned to help pull or push it along to the nearest siding?

[chrisvandenkieboom]

Nov 9, 2011 9:14:03 GMT trc666 said:

nick0323, I imagine your station would have been Highbury & Islington, Warren Street or Victoria, as south-to-north trains can reverse directly off the platform with passengers at those stations.

So can the Picc at KX. Happened on that day in August. If that's what you mean.

[Deleted]

For the Jubilee, surely bi-di Stratford to Waterloo would have been useful - there are enough cross-overs to turn trains around, Waterloo, London Bridge, Canary Wharf, North Greenwich and West Ham through to Stratford. I think there is a bit of bi-di West Ham to Stratford as I was on a Jubilee train which crossed over near the staff halt onto the Eastbound and then a train on the normal approach went into platform 13 and the train I was on went into 15 at the same time! Weird having two trains race into Stratford in the same direction alongside each other.

[Deleted]

Nov 10, 2011 1:02:43 GMT railtechnician said:

Nov 9, 2011 17:21:43 GMT @delboy200 said:

Isn't bi-di helpful if a train cant move itself under its own power and a train can be summoned to help pull or push it along to the nearest siding?

Nope, not unless it is going to be a regular event! Rules rather than signals are used to aid stalled or otherwise disabled trains!

No point it being a signalled move, ATP's are there to stop you entering tracks occupied by other trains, so the moves have to be done in slow manual anyway!!

[1018509]

Nov 9, 2011 8:42:26 GMT @xercesfobe said:

Interestingly on the BART network in California bi-directional working is common, however from my experience it tends to be between stations only.

XF

Pardon my sense of humour but how else can trains run but between stations?

[1018509]

Rayners Lane is bi-directional from both platforms.

[trc666]

That's due to the siding at one end and two trailing crossovers at the other (one for each branch)

[100andthirty]

A number of important points have been made:

Any signalling system can be bi-di... otherwise terminal platforms and other reversing points wouldn't work

To make bi-di really useful, many more crossovers than is typical for the tube would be required.

There's more to making a system bi-di than the signalling. Designing the points and track with this in mind is also useful.

SSR signalling will be bi-di, Jubilee signalling is bi-di - but the whole Jubilee railway system isn't.

[Deleted]

When you say Jubilee is bi-di, I think that is rather exaggerating the meaning! A small bit of bi-di in and out of terminal platforms and depots is hardly what we are talking about here.

Jubilee is NOT bi-di anymore than any other underground line at present.

DLR is fully bi-di - this is what this thread was getting at, and in particular why a system such at that installed on Jubilee (i.e. virtually the same as DLR) why is wasn't just put in with bi-di.

With SSR - is that going to be fully bi-di in the true sense, or just 'terminus and turnbacks' like the Jubilee and other lines

[jardine01]

I agree Bi- Di is silly why would you go the wrong way up the line?

[v52gc]

Nov 27, 2011 16:35:34 GMT @jardine01 said:

I agree Bi- Di is silly why would you go the wrong way up the line?

If the running line is bi-di you wouldn't be going the wrong way!
Maybe signage would be a little confusing but DMIs could be accurate. It would mainly be useful during service disruptions.

[norbitonflyer]

There is a long (four mile) stretch of bi-di on the Met: the Chesham branch.

[Deleted]

Nov 27, 2011 16:35:34 GMT @jardine01 said:

I agree Bi- Di is silly why would you go the wrong way up the line?

In 2005 the jubilee ran single line on a weekend or two between Kingsbury and Stanmore to allow a service to continue whilst Wembley Park was being refurbished. This meant a service could still be run without forcing everyone onto rail replacement buses. This would obviously not been possible under the current system.

[v52gc]

Nov 27, 2011 20:58:17 GMT @delboy200 said:

Nov 27, 2011 16:35:34 GMT @jardine01 said:

I agree Bi- Di is silly why would you go the wrong way up the line?

In 2005 the jubilee ran single line on a weekend or two between Kingsbury and Stanmore to allow a service to continue whilst Wembley Park was being refurbished. This meant a service could still be run without forcing everyone onto rail replacement buses. This would obviously not been possible under the current system.

I thought that was done using single line working, a procedure and nothing to do with signalling (whatever the type) other than points secured.

[mrfs42]

Nov 27, 2011 20:58:17 GMT @delboy200 said:

This would obviously not been possible under the current system.

It was done under 'trains locked in' - there's a post somewhere on the Forum that I wrote up about it - I have a copy of the TTN too.

I think that there's absolutely nothing stopping this repeating itself, apart from the fact that a) the procedure probably hasn't been written and b) there would need to be some temporary bang road stopping marks. It'd be rather slow though, I should imagine.

With the correct clipping, scotching and PNX/other protection malarkey the two trains could run in complete safety - remember these are two trains, each captive on their own line.

[100andthirty]

Nov 27, 2011 15:48:40 GMT @sw206 said:

When you say Jubilee is bi-di, I think that is rather exaggerating the meaning! A small bit of bi-di in and out of terminal platforms and depots is hardly what we are talking about here.

Jubilee is NOT bi-di anymore than any other underground line at present.

NO, I wasn't exaggerating the meaning. the Jubilee signalling system is inherently bi-di, but the railway isn't, so the bi di capability isn't able to be used.

The intent for SSR is that the inherently bi-di sytem being purchased will be able to be used in that way and not just at terminals and reversing points.

[Chris M]

Nov 27, 2011 16:35:34 GMT @jardine01 said:

I agree Bi- Di is silly why would you go the wrong way up the line?

Bi directionality is useful if there is a problem on the line.
A couple of recent experiences of mine on the DLR illustrate to illustrate this.

There was a failed train (I think) between Cyprus and Gallions Reach. Trains from the west ran as normal into the westbound platform at Prince Regent and then reversed back east, crossing over to the westbound line between there and Custom House. Meanwhile a single-train shuttle service was running on the westbound line between Prince Regent and Cyprus. No points needed to be clipped or scotched, and it didn't take long to set up.

Approaching the end of service one night, there was a queue of three or four eastbound trains waiting to get into Gallions Reach (the delay being caused by the length of time it takes to ensure the train is empty before heading to the depot). So the ex-Stratford International train I was on that was heading for Beckton ran wrong road from Prince Regent through to Beckton, bypassing the queue at Gallions. There were no westbound trains in the way (if there were any more that night, they were in the queue or already west of Prince Regent).

The flexibility to do things like this is the benefit of bi-directional signalling.

[Deleted]

Dec 2, 2011 6:04:39 GMT 100andthirty said:

NO, I wasn't exaggerating the meaning. the Jubilee signalling system is inherently bi-di, but the railway isn't, so the bi di capability isn't able to be used.

This is correct. Seltrac is bi-directional capable. That functionality wasn't designed out for Jubilee and Northern but the PPP Contract didn't incentivise its use enough. Thus the system testing to enable it to be used and the infrastructure mods (to current rails, point locks etc.) were not done.

[Ben]

So, if anyone would be prepared to stomache another lengthy round of closures, it would be possible to fully commission such a feature, instead of letting it lay 'dormant'? Thats interesting as Mike Brown in an address to the assembleys transport comittee gave an extremely stong impression that the whole ability was removed at extra expense from the default options...

[tubeprune]

In my view, there is little value in providing bi-di running on the Underground these days. The volume of passengers is such that if you allow a line to remain open, a single track train service over a section would be overwhelmed by passengers and trains would be detained for long periods in tunnels waiting for access to stations.

Bi-di isn't worth the expense. What is needed is a better response to technical failures. It is currently far too slow and bogged down by restrictive rules.

[jardine01]

I could not agree more it would be daft to have single line working over an section this would just cause delays and would slow the line down.

[Deleted]

Dec 2, 2011 22:09:45 GMT Ben said:

So, if anyone would be prepared to stomache another lengthy round of closures, it would be possible to fully commission such a feature, instead of letting it lay 'dormant'? Thats interesting as Mike Brown in an address to the assembleys transport comittee gave an extremely stong impression that the whole ability was removed at extra expense from the default options...

There were all sorts of stories about in the days of the PPP. It was certainly said in various forums and meetings internally that the ability was removed. But, if you think about it bi-directional running is possible in and out of sidings, terminal platforms, into and from the "dip" at Neasden and most notably along the "long route" into Stratford from West Ham on the westbound road.

I would be interested in seeing the wording of the address you refer to above.

[andypurk]

The C2C mainline, from Fenchurch Street, has bi-directional availability most of the way to Shoeburyness (although the line via Tilbury doesn't). This capability gets used regularly at weekends to allow engineering work to happen (including on the District line in the past), whilst allowing a train service to be maintained on a single track past the works.

Introducing this sort of operation on LU would certainly be justified, even including the necessary extra crossovers, to allow engineering works to close one track whilst maintaining a lower frequency early morning / late evening service. The extended part of the Jubilee line could probably make use of such a facility and still allow a reasonable frequency; especially if the crossovers at Waterloo and London Bridge had been provided in a scissors arrangement rather than as single crossovers.