Why two lines for Tyne & Wear Metro?

[ariford113]

Is there any reason why T&W Metro has two seperate lines, rather than running to/from alternate destinations, i.e. four services

Airport <-> South Shields
Airport <-> South Hylton
St James <-> South Shields
St James <-> South Hylton

This would seem to provide a better service without being much more complicated.

 

[Ianno87]

Is there any reason why T&W Metro has two seperate lines, rather than running to/from alternate destinations, i.e. four services

Airport <-> South Shields
Airport <-> South Hylton
St James <-> South Shields
St James <-> South Hylton

This would seem to provide a better service without being much more complicated.

Problem with that would be to get an even interval service on, say, the Airport branch every 12 minutes, and an even service via the Coast every 12 minutes, and an even headway through the City Centre (every 6 minutes), you'd need 6/18/6/18 intervals on both the South Shields and South Hylton branches.

Even services on all branches and through the centre is more important, especially given that easy same-platform changes are available when you don't have a direct service.

 

[gordonthemoron]

well that's what S-Bahns do, so I presume it's the most practical

 

[rebmcr]

Problem with that would be to get an even interval service on, say, the Airport branch every 12 minutes, and an even service via the Coast every 12 minutes, and an even headway through the City Centre (every 6 minutes), you'd need 6/18/6/18 intervals on both the South Shields and South Hylton branches.

Even services on all branches and through the centre is more important, especially given that easy same-platform changes are available when you don't have a direct service.

well that's what S-Bahns do, so I presume it's the most practical

Crossrail too, there will not be any Heathrow ↔ Shenfield, nor any Reading ↔ Abbey Wood services because of this mathematical quirk.

 

[hacman]

The service frequency is such that there isn't really demand for this, and it makes it much more simple for passengers that trains follow a fixed set of routes.

 

[John Griffiths]

The trouble is that you get used to that and so when there is a choice... Well, let's just say that when I travel from the city centre back towards my home station of Regent Centre it's not unknown for me to end up getting off at Longbenton, crossing the footbridge, getting a train one stop to South Gosforth, getting off and crossing the footbridge, and getting a third train one stop to Regent Centre.

 

[Tetchytyke]

This would seem to provide a better service without being much more complicated.

The basic frequency is every 12 minutes on each line, with it being every 6 minutes in the core. Effectively it's two branches each side of the core.

As it stands, the service is, northbound:
South Hylton - Airport
South Shields - St James via the Coast
South Hylton - Airport
South Shields - St James via the Coast

Change it and you get:
South Hylton - Airport
South Shields - Airport
South Hylton - St James via the Coast
South Shields --St James via the Coast.

So instead of a neat 5tph on each branch, all at 12 minute gaps, you get two trains in 6 minutes then nothing for 18 minutes. Clearly a much worse service.

 

[willgreen]

The basic frequency is every 12 minutes on each line, with it being every 6 minutes in the core. Effectively it's two branches each side of the core.

As it stands, the service is, northbound:
South Hylton - Airport
South Shields - St James via the Coast
South Hylton - Airport
South Shields - St James via the Coast

Change it and you get:
South Hylton - Airport
South Shields - Airport
South Hylton - St James via the Coast
South Shields --St James via the Coast.

So instead of a neat 5tph on each branch, all at 12 minute gaps, you get two trains in 6 minutes then nothing for 18 minutes. Clearly a much worse service.

I think this is because of the South Tyneside freight line, which causes a single Metro line in some places? The current plan is to redouble that to allow running of Metro and freight trains on the same line, which should lead to an even 6tph (IIRC).

 

[Tetchytyke]

The current plan is to redouble that to allow running of Metro and freight trains on the same line, which should lead to an even 6tph (IIRC).

It will add capacity for events (think the GNR) but it won't, by itself, change the basic frequency. The single track sections are Pelaw-Hebburn and Hebburn-Jarrow, which is after the lines split.

There are two branches north/east of South Gosforth, and two branches south/east of Pelaw. You can't avoid an irregular frequency on one of the branches unless you keep separate lines. It's why the Metro has always had separate lines, although the South Shields trains always used to go to the airport and the Sunderland trains to St James via the Coast.

 

[hacman]

It will add capacity for events (think the GNR) but it won't, by itself, change the basic frequency. The single track sections are Pelaw-Hebburn and Hebburn-Jarrow, which is after the lines split.

There are two branches north/east of South Gosforth, and two branches south/east of Pelaw. You can't avoid an irregular frequency on one of the branches unless you keep separate lines. It's why the Metro has always had separate lines, although the South Shields trains always used to go to the airport and the Sunderland trains to St James via the Coast.

The ambition is to increase service frequencies when the single sections are removed - this is why Metro Flow includes the procurement of 4 extra trains.

See https://www.nexus.org.uk/metro-flow and https://www.nexus.org.uk/news/item/our-ps100m-project-boost-frequency-and-reliability-metro

 

[swt_passenger]

I think this is because of the South Tyneside freight line, which causes a single Metro line in some places? The current plan is to redouble that to allow running of Metro and freight trains on the same line, which should lead to an even 6tph (IIRC).

This isn’t actually directly relevant to the original question about operating 4 service patterns though, exactly the same issues would arise with 6 tph (10 minute interval) except on two of the branches you now get 5/15/5/15 gaps between trains, instead of the 6/18/6/18 already noted.

As reply #2 noted, and reply #7 repeated, it is impossible to have four route permutations AND an even frequency on all four branches.

 

[willgreen]

This isn’t actually directly relevant to the original question about operating 4 service patterns though, exactly the same issues would arise with 6 tph (10 minute interval) except on two of the branches you now get 5/15/5/15 gaps between trains, instead of the 6/18/6/18 already noted.

As reply #2 noted, and reply #7 repeated, it is impossible to have four route permutations AND an even frequency on all four branches.

Yep, misread the post I was originally replying to - sorry!

 

[swt_passenger]

Yep, misread the post I was originally replying to - sorry!

No problems. But as I wondered earlier, there must be a mathematical or logical proof, someone must know it...

I remember a conversation in the forums a few years back about TPE, and it was being asked why their two trains couldn’t be half an hour apart at Newcastle, and I’m pretty sure the answer was because they wanted alternate Liverpool and Manchester Airport services, and the only way to get a clock face timing at Newcastle was if both trains went to the same destination. But the priority was to alternate Liverpool and Man Air on the 4 tph 15 min interval service through their core route. (At that time anyway.)

 

[Ianno87]

No problems. But as I wondered earlier, there must be a mathematical or logical proof, someone must know it...

I remember a conversation in the forums a few years back about TPE, and it was being asked why their two trains couldn’t be half an hour apart at Newcastle, and I’m pretty sure the answer was because they wanted alternate Liverpool and Manchester Airport services, and the only way to get a clock face timing at Newcastle was if both trains went to the same destination. But the priority was to alternate Liverpool and Man Air on the 4 tph 15 min interval service through their core route. (At that time anyway.)

Plus, in Newcastle's case, having the TPE services slightly bunched helps flight all the passenger services between Northallerton and Newcastle to accommodate a freight path.

 

[Tetchytyke]

The ambition is to increase service frequencies when the single sections are removed

I'll believe it when I see it, as the single line used to manage 6tph. It'll definitely help on GNR day and will also help in disruption.

 

[Ianno87]

I'll believe it when I see it, as the single line used to manage 6tph. It'll definitely help on GNR day and will also help in disruption.

There's "managing 6tph" and "managing 6tph reliably".

Presumably the former 6tph South Shields service also pre-dates that South Hylton extension and the added little bit of unreliability that brought.

Plus you might get the best journey times out of the new stock if it's not limited by waiting for single lines.

 

[hacman]

I'll believe it when I see it, as the single line used to manage 6tph. It'll definitely help on GNR day and will also help in disruption.

Exactly, so the line can handle that to an extent now. The issues are caused by the timing issues around the single track, and the fact that the extension to South Hylton made things considerably more complicated due to having to plan conflicting movements - things which more rolling stock and removal of the single sections will help fix. The fleet being more thinly spread and their age hasn't helped either.

Nexus won a £95million funding package from the government for this - funding which had to be supported by a business case, feasibility studies and more. Let's also remember that the Transforming Cities fund from which this money was allocated was also a fixed pot, allocated in a competition style - so not only did the business case and other supporting elements for this project validate the ambition, but they also did so better than competing bids.

Personally I'd be very surprised if they do not deliver on this. For one, there will be very heavy scrutiny if Nexus take the money and don't produce the expected results.

 

[ModernRailways]

I'll believe it when I see it, as the single line used to manage 6tph. It'll definitely help on GNR day and will also help in disruption.

It will be 6tph on both lines (a 10 minute frequency) during the day. I believe the latest plan is to drop to 3tph (a 20 minute frequency) on an evening (dependant on driver training).

The single line can support more (I believe there has been more than 10tph in that section not timetabled, but for testing purposes). As mentioned though doing it reliably is a challenge. One slight 2 minute delay can cause another train a 5+ minute delay as it waits for the other train. I haven't been round this section for a while but it was always particularly noticeable when heading towards Newcastle, if the train to South Shields is 2 minutes late, you will sit and wait at Jarrow till it arrives from Hebburn. Once you reach Hebburn, you're running around 3/4 minutes late and when you get to the next single section you will sit and wait for the next South Shields to come down from Pelaw making the delay potentially 6-8 minutes. Once you're at Pelaw you may get stuck behind the Airport train, or sit on the ramp up to Pelaw junction waiting for the South Hylton train to cross in front.

 

[Scott M]

It will add capacity for events (think the GNR) but it won't, by itself, change the basic frequency. The single track sections are Pelaw-Hebburn and Hebburn-Jarrow, which is after the lines split.

There are two branches north/east of South Gosforth, and two branches south/east of Pelaw. You can't avoid an irregular frequency on one of the branches unless you keep separate lines. It's why the Metro has always had separate lines, although the South Shields trains always used to go to the airport and the Sunderland trains to St James via the Coast.

Why did they change it so that South Shields runs to St James now instead of Airport?

 

[Ianno87]

Why did they change it so that South Shields runs to St James now instead of Airport?

I'd always assumed it was to give Sunderland a direct Airport link.

 

[Scott M]

I'd always assumed it was to give Sunderland a direct Airport link.

My thoughts had been to even out the route time to help plan driver shifts (as opposed to having one extremely long route and one short route), but that makes more sense.

 

[Ianno87]

My thoughts had been to even out the route time to help plan driver shifts (as opposed to having one extremely long route and one short route), but that makes more sense.

That's a reasonable thought too: South Hylton to St James via The Coast would be very long in one go.

 

[hacman]

Why did they change it so that South Shields runs to St James now instead of Airport?

Quite simply it was to reduce the length of the yellow route, as St James to South Hylton being so long meant disruptions easily amplified.

Given that south of Pelaw Metro operates as a normal TOC with delay penalties and having to fit between the other operators, there was a very strong incentive for this.

 

[Scott M]

Quite simply it was to reduce the length of the yellow route, as St James to South Hylton being so long meant disruptions easily amplified.

Given that south of Pelaw Metro operates as a normal TOC with delay penalties and having to fit between the other operators, there was a very strong incentive for this.

Makes sense, cheers for that.

 

[deep south]

I guess there is also the added complication of sharing the NR lines to Sunderland with the odd Grand Central service and the various Northern trains as well to take into account. The GC turnarounds in Sunderland are pretty short as it is!