Todmorden Curve

[Joseph_Locke]

While we are on the matter of the Blackburn to Bolton line (albeit somewhat off-topic), what is the most current Network Rail position on the matter of the Sough tunnel.

I'd hate to speak for them, but it appears to be "leave well alone".

 

[Sox]

On paper, yes, but the limited passing opportunities means that as soon as the slightest thing goes wrong it all goes wrong. Introducing a fourth train per hour in the off-peak will cause this failed state to last all day ...

Secondly, the line is not going to be fully re-doubled, nor electrified, this side of CP6 at least.

Thanks for your interesting insights.

Rail track planning theory not my bag but, in layman's terms, is it as simple as saying that the more/longer loops there are, the probability of a breakdown (helpfully!) occurring at a loop position becomes greater?

...are the up/down tracks forming the loop always by-directional? Is this what you meant by your former colleagues comment above, i.e without proper signalling, all a loop provides is a mono-directional, broken down train "parking" facility?

....and, for this type single/loop mixed track layout, the issue of managing breakdowns becomes the one overriding factor when approaching peak capacity?

Regards

Sox

 

[edwin_m]

It's not really a question of breakdowns. If a train breaks down it is a matter of pot luck where it happens to be and what can be done about it, though I guess if it is on a loop or double track it is easier to keep something running than if it is on a single line. As to bi-directional signalling on loops, there is no hard and fast rule, some are some aren't.

Much more important is what happens when a train is delayed. Trains in opposite directions are timetabled not to meet on single line sections. However if one train is late its revised timings might meet those of another train on the single line. The signalling wouldn't allow this so there is no safety issue, but one train will have to wait for the other one so either the late train will get even later or the other one will become late.

This problem can be reduced if there are extra loops which may not be used in the normal timetable but allow trains to pass there if the service is disrupted.

 

[The Planner]

Rail track planning theory not my bag

I hope the space was intentional there!

The loop won't be bi-di, would cost too much, the Darwen solution looks to be a low cost option that allows a train to see a green aspect coming into the station /loop if one in the other direction is doing the same thing. This appears to suggest that timetable resilience isn't going to be massive or one train is going to have a large-ish dwell in one direction.

 

[HowardGWR]

It's not really a question of breakdowns. If a train breaks down it is a matter of pot luck where it happens to be and what can be done about it, though I guess if it is on a loop or double track it is easier to keep something running than if it is on a single line. As to bi-directional signalling on loops, there is no hard and fast rule, some are some aren't.

Much more important is what happens when a train is delayed. Trains in opposite directions are timetabled not to meet on single line sections. However if one train is late its revised timings might meet those of another train on the single line. The signalling wouldn't allow this so there is no safety issue, but one train will have to wait for the other one so either the late train will get even later or the other one will become late.

This problem can be reduced if there are extra loops which may not be used in the normal timetable but allow trains to pass there if the service is disrupted.

I think we see this a lot on the Salisbury to Exeter stretch. I have seen situations on Realtime trains where one wondered if one train was not being allowed to be very, very, late in order to produce a better percentage of trains arriving within PPM limit by holding it up in one of the loops to allow the other(s) to remain within PPM limit. I have wondered whether there are any rules or checks on this possible issue, by the ORR.

 

[The Planner]

Surely that is the idea? Reduce overall delay even if it means battering one train that cannot ever make PPM against those that will?

 

[61653 HTAFC]

Surely that is the idea? Reduce overall delay even if it means battering one train that cannot ever make PPM against those that will?

Pretty much. It happens a lot on the Penistone line- if the 'Up' (ex-HUD) service is on time when it reaches Clayton West Junction (end of the Stocksmoor/Shepley loop) but the 'down' is running late and has not yet reached Penistone, the up train will often be allowed into the single-line section through Denby Dale with the down held at PNS to cross there.

 

[HowardGWR]

Pretty much. It happens a lot on the Penistone line- if the 'Up' (ex-HUD) service is on time when it reaches Clayton West Junction (end of the Stocksmoor/Shepley loop) but the 'down' is running late and has not yet reached Penistone, the up train will often be allowed into the single-line section through Denby Dale with the down held at PNS to cross there.

But it can mean that the pax on the one extra late train are purposely inconvenienced just for the sake of performance statistics, whereas both trains could be slightly inconvenienced with the other approach, not a morally justified attitude, I suggest.
--- old post above --- --- new post below ---

Surely that is the idea? Reduce overall delay even if it means battering one train that cannot ever make PPM against those that will?

See my reply above.

 

[The Planner]

Wasn't it Spock that said the needs of the many outweigh those of the few?

 

[DarloRich]

It seems madness that such a short bit of track will open up so many seemingly simple journey options!

 

[30907]

But it can mean that the pax on the one extra late train are purposely inconvenienced just for the sake of performance statistics, whereas both trains could be slightly inconvenienced with the other approach, not a morally justified attitude, I suggest.

Not just a question of performance minutes - having a train several minutes late at Meadowhall (and even at Barnsley, given the signalling) is going to have significant knock-on effects on other trains, all with passengers, whereas a Huddersfield-bound train running late delays no other trains (one evening peak exception), inconvenient though it may be for its own passengers.

 

[Deerfold]

Wasn't it Spock that said the needs of the many outweigh those of the few?

I suspect he wasn't the first to say it.

Especially as he won't say it until the 23rd century

 

[34D]

Better yet why don't we go the whole hog? Let's have an hourly Colne - Burnley - Blackburn - Bolton - Man Vic - Todmorden - Burnley - Blackburn - Preston - Blackpool South service, alternating with an hourly Colne - Blackburn - Preston - Carnforth - Hellifield service. On reaching Hellifield the service could split, with one portion running to Clitheroe, Blackburn, Bolton and on to Manchester Airport. The other portion could go Skipton - Leeds - Bradford Interchange - Halifax - Hebden Bridge - Burnley - Blackburn - Preston - Blackpool North.

Of course some cynical people might say all this is a tad OTT for a line that carries a massive 700 passengers per day on average.

Anyway - back on topic. Is there any update on how the actual work in the real world is progressing? It was reported as being 48hrs ahead of schedule but we've had some pretty lousy weather recently.

Incidentally it looks as though there are track renewal works imminent on the Colne branch, with stacks of steel sleepers and bags of ballast appearing trackside.

What about dropping a portion at Shipley, which then goes Guiseley-ilkley-embsay-skipton-colne (via two reopened stretches of track)? Also the Skipton-London class 91 should be extended to Colne over the new route, maybe starting at Todmorden, and reversing at Blackburn, hauled by a class 37 from Tod to Blackburn then a class 47 Blackburn to Colne where it then puts it's pantograph up?

 

[Xenophon PCDGS]

What about dropping a portion at Shipley, which then goes Guiseley-ilkley-embsay-skipton-colne (via two reopened stretches of track)? Also the Skipton-London class 91 should be extended to Colne over the new route, maybe starting at Todmorden, and reversing at Blackburn, hauled by a class 37 from Tod to Blackburn then a class 47 Blackburn to Colne where it then puts it's pantograph up?

Do not ask for realism, as a refusal often offends..

 

[Sox]

some interesting responses but if all the redoubling achieves is a marginal increase in overlap between two trains (surely, in the case of Darwen, the overlap will be measured in low single digit minutes) what real difference will it make apart from a bit of tweaking of the timetable?

Of course what is really required is an extra single track bridge over the M65, a rebore of the Sough tunnel and full redoubling between Blackburn and Bolton at heaven knows what cost.

 

[Joseph_Locke]

some interesting responses but if all the redoubling achieves is a marginal increase in overlap between two trains (surely, in the case of Darwen, the overlap will be measured in low single digit minutes) what real difference will it make apart from a bit of tweaking of the timetable?

Of course what is really required is an extra single track bridge over the M65, a rebore of the Sough tunnel and full redoubling between Blackburn and Bolton at heaven knows what cost.

For a very specific value of "what is required". If all your services are diagrammed for 150s (or looking ahead 319) and the all go to Clitheroe and back at 2 tph each way, why do you need to re-double the whole line?

The difference it makes is to increase the available "window" of passing time from two minutes to about five, which allows 2tph each way to work under 99.99% of opoerating conditions.

In tunnel terms, a new alignment under Shap and a new pair of Woodheads would be quite a lot higher up the shopping list than Sough.

 

[Xenophon PCDGS]

For a very specific value of "what is required". If all your services are diagrammed for 150s (or looking ahead 319) and the all go to Clitheroe and back at 2 tph each way, why do you need to re-double the whole line?

Your posting of 319s running to Clitheroe is a scenario that I must admit that I had never envisaged. You have given me an early Monday morning to ponder upon this matter whilst reading the March issue of Modern Railways.

 

[Techniquest]

Your posting of 319s running to Clitheroe is a scenario that I must admit that I had never envisaged. You have given me an early Monday morning to ponder upon this matter whilst reading the March issue of Modern Railways.

Funnily enough, I had to re-read that bit about possible 319s through Blackburn in the future, still seems like a madman's dream that there will be 319s operating with Northern soon.

Unlike yourself, however, my pondering of it will be whilst travelling on the bus to Hereford tomorrow morning!

 

[pemma]

According to Burnley Borough Council chief executive Steve Rumbelow the carriages needed for Blackburn to Manchester via Burnley have been confirmed as being available from December 2014 and won't be affected by the fact Chiltern have taken on the TPE 170s and Northern are expected to provide trains to meet the short fall.

 

[Xenophon PCDGS]

According to Burnley Borough Council chief executive Steve Rumbelow the carriages needed for Blackburn to Manchester via Burnley have been confirmed as being available from December 2014 and won't be affected by the fact Chiltern have taken on the TPE 170s and Northern are expected to provide trains to meet the short fall.

What type of "carriages" are being made available in December 2014....or are we not to know until the first of the ex-Merseyrail Class 142 Pacers suddenly pulls into Blackburn station from the depot to run the inaugural service...

 

[pemma]

What type of "carriages" are being made available in December 2014....or are we not to know until the first of the ex-Merseyrail Class 142 Pacers suddenly pulls into Blackburn station from the depot to run the inaugural service...

The first clue will be what trains are used on the Victoria-Todmorden service that starts in May, given those services will be extended to Blackburn via Burnley when the extra unit becomes available.

The units which should be freed up by EMUs in December are all Sprinters and mainly 156s but that doesn't mean one of those will directly go on to the new service.

 

[Xenophon PCDGS]

The units which should be freed up by EMUs in December are all Sprinters and mainly 156s but that doesn't mean one of those will directly go on to the new service.

I do so admire the phraseology used in the final part of your posting.

 

[natureboy]

Has anyone else noticed what I have today?

The title of this thread "The Todmorden Curve" has been added to the MetroTrain map.

 

[Deerfold]

Has anyone else noticed what I have today?

The title of this thread "The Todmorden Curve" has been added to the MetroTrain map.

Where's that? I can't see it on this one:

http://www.wymetro.com/traintravel/InteractiveMap/

Or this one..

http://www.wymetro.com/uploadedFile...vel/traintimetables/Rail-network-map-2013.pdf

 

[Geeves]

Id say there is a 100% chance you will see 142s on the Blackburn - Burnley - Manchester job! Before 142s from Manchester in the Blackburn direction were relatively rare due to not being cleared to Clitheroe, that of course is no longer the case. The Ribble Valley is now in the same Merseyrail 142 as everyone else! Haha

 

[Xenophon PCDGS]

Id say there is a 100% chance you will see 142s on the Blackburn - Burnley - Manchester job! Before 142s from Manchester in the Blackburn direction were relatively rare due to not being cleared to Clitheroe, that of course is no longer the case. The Ribble Valley is now in the same Merseyrail 142 as everyone else! Haha

This of course will imbue the new rail service with the image that Northern Rail have made such strident attempts to keep as the true picture of the Northern Rail franchise....

 

[Lankyline]

What type of "carriages" are being made available in December 2014....or are we not to know until the first of the ex-Merseyrail Class 142 Pacers suddenly pulls into Blackburn station from the depot to run the inaugural service...

Maybe a 3 coach non corridor train pulled by a BR standard tank ?????? got to admit better than a pacer !

 

[L&Y Robert]

Maybe a 3 coach non corridor train pulled by a BR standard tank ?????? got to admit better than a pacer !

Aha! That's what they used to be. Todmorden to Blackpool. Took it every Saturday for some years, we got off at Manchester Road - close by our house.

 

[Welshman]

Maybe a 3 coach non corridor train pulled by a BR standard tank ?????? got to admit better than a pacer !

Or a 2-car Rolls-Royce-engined Cravens dmu - as experienced the last time I rode the Todmorden curve!

 

[chorleyjeff]

Or a 2-car Rolls-Royce-engined Cravens dmu - as experienced the last time I rode the Todmorden curve!

Raise you to LMS corridor carriage with temp table provided by guard on request with Black 5 at the front!