Metrolink - tram frequency

[deltic]

What is the highest frequency of service that can be provided on Manchester's metrolink?

With HS2 and if full Northern Hub is eventually delivered, far more people will be passing through Piccadilly station and wanting to travel onwards throughout the city. Realistically how many more services could be provided on Metrolink without further upgrades? I know the context is different but compared to most urban metro systems frequency of service on British tram networks always seems quite low and I wondered if there are any technical or operational reasons for this.

 

[edwin_m]

It will be up to around 40 trams per hour on some legs of the city centre network.

 

[gordonthemoron]

they would probably need to ensure double trams on all services

 

[nerd]

What is the highest frequency of service that can be provided on Manchester's metrolink?

With HS2 and if full Northern Hub is eventually delivered, far more people will be passing through Piccadilly station and wanting to travel onwards throughout the city. Realistically how many more services could be provided on Metrolink without further upgrades? I know the context is different but compared to most urban metro systems frequency of service on British tram networks always seems quite low and I wondered if there are any technical or operational reasons for this.

The key constraint on frequency, is the number of services that can run across the city from west to east; which is why the Second City Crossing is under construction now. TfGM commissioned a modelling exercise a few years back, which showed that the limit on 1CC for regular services would be 25 tph in each direction. 2CC will likely be the same; so up to 50 tram services per hour could run across the city in each direction.

In the model service configuration that TfGM prepared for bidders to run the Metrolink franchise from 2017 onwards, they show 25 tph along 2CC, and 20 tph along 1CC. That then allows for 10 tph as standard on all seven major Metrolink lines - Ashton, E Didsbury, Airport, Altrincham, Eccles/Mediacity, Bury and Shaw/Rochdale. The Trafford Centre line would run 5 tph through to Crumpsall.

With that configuration, there would be 20 tph services running into Piccadilly from the west, but only 10 tph carrying on eastwards to Ashton; so it would be possible for 10 tph east-side tram-train services (likely from Marple and Bredbury) to link into to 'spare' west-side paths; and it would also be possible - given that there would only be 20 tph along 1CC, for 5 tph further east-side services to run into Piccadilly.

So, in principle, we might expect Piccadilly to be handling up to 25 tram and tram-train services per hour in each direction; in recognition of which it appears to be assumed that the Piccadilly Metrolink stop is likely to be relocated in association with the HS2 programme, and expanded to have four platform faces. In principle (and likely in practice) most of these services would be run as doubles with a capacity of 400 passengers on each, so the total hourly capacity of the Piccadilly Metrolink stop would be 20,000 - slightly more than the entire capacity of the HS2 system into Old Oak Common and Euston.

 

[deltic]

Nerd thanks for that comprehensive reply - what is the 25tph constraint caused by? Presumably in the city centre trams are not controlled by signals but driven under line of sight. Is the constraint more the impact on other road traffic?

 

[edwin_m]

In the model service configuration that TfGM prepared for bidders to run the Metrolink franchise from 2017 onwards, they show 25 tph along 2CC, and 20 tph along 1CC. That then allows for 10 tph as standard on all seven major Metrolink lines - Ashton, E Didsbury, Airport, Altrincham, Eccles/Mediacity, Bury and Shaw/Rochdale. The Trafford Centre line would run 5 tph through to Crumpsall.

This results in 45TPH between Cornbrook and St Peters Square. That is more than the 40TPH maximum I suggested above, but that is more for street running based on Kaiserstrasse in Karlsruhe which is not far off being a "wall of trams" at times (maybe in the past now, not sure of the status of the bypassing tunnel).

With no vehicles or pedestrians to worry about, it will be interesting to see how many more the viaduct section can take before tram queues become unacceptable at the stops where all trams in a particular direction have to use one platform.

 

[snowball]

The key constraint on frequency, is the number of services that can run across the city from west to east; which is why the Second City Crossing is under construction now.

The Second City Crossing runs north-south. North is at the top in this map.

http://www.tfgm.com/Corporate/Consultations/Metrolink2cc/Documents/2CC-stops-map.pdf

 

[nerd]

Nerd thanks for that comprehensive reply - what is the 25tph constraint caused by? Presumably in the city centre trams are not controlled by signals but driven under line of sight. Is the constraint more the impact on other road traffic?

Chiefly constrained by the traffic-light intersections along Mosley Street. Trams usually have priority at traffic lights, but when the frequency goes above 25 tph, this priority cannot be maintained; resulting in some trams having to wait a period for the lights to change. Which in turn means that the timetable-keeping deteriorates sharply.

Which is not to say that 25 tph is an absolute limit; only the maximum that maintains a regular timetable. In the event of an incident - when tram units may be temporarily stranded one side or another of the city centre - 1CC can easily accommodate 35 or 40 services in an hour over the recovery period. This is a key advantage in line-of-sight operation; if the city centre crossing were controlled by block signalling (as would be the case if there was common tunnel running under the city centre) then services would be far less resilent to interruptions. Hence, although Metrolink core maximum capacity is only slightly higher than that on DLR (24 tph), or T&W Metro (20 tph), in practice it is much less severely constrained.

 

[deltic]

Chiefly constrained by the traffic-light intersections along Mosley Street. Trams usually have priority at traffic lights, but when the frequency goes above 25 tph, this priority cannot be maintained; resulting in some trams having to wait a period for the lights to change. Which in turn means that the timetable-keeping deteriorates sharply.

Which is not to say that 25 tph is an absolute limit; only the maximum that maintains a regular timetable. In the event of an incident - when tram units may be temporarily stranded one side or another of the city centre - 1CC can easily accommodate 35 or 40 services in an hour over the recovery period. This is a key advantage in line-of-sight operation; if the city centre crossing were controlled by block signalling (as would be the case if there was common tunnel running under the city centre) then services would be far less resilent to interruptions. Hence, although Metrolink core maximum capacity is only slightly higher than that on DLR (24 tph), or T&W Metro (20 tph), in practice it is much less strongly constrained.

Thanks nerd very helpful

 

[Greybeard33]

Perhaps worth adding that power supply strengthening would be needed to run all services as doubles. I understand the substations on the Bury and Altrincham lines are near capacity with the current 10tph service of alternating singles and doubles.

 

[WatcherZero]

Adding substation capacity and another turnback to the Bury line is included as part of the Trafford line works.

 

[telstarbox]

With the Northern Hub, more National Rail trains will call at both Piccadilly and Victoria so there will be less demand for trips within the city centre.

 

[Bungle965]

Adding substation capacity and another turnback to the Bury line is included as part of the Trafford line works.

That is great news, additional capacity is greatly needed on the Bury line especially in the peaks when single trams are unsuitable for the amount of people.
Sam

 

[Altfish]

That is great news, additional capacity is greatly needed on the Bury line especially in the peaks when single trams are unsuitable for the amount of people.
Sam

Currently, every other tram is a double on the Bury line. Same on the Altrincham line.

 

[Bungle965]

Currently, every other tram is a double on the Bury line. Same on the Altrincham line.

Yes it is however that still is not enough to deal with the amount of people. The sooner the substations are upgraded the better.
Sam

Sent from my ONEPLUS A3003 using Tapatalk

 

[Altfish]

Yes it is however that still is not enough to deal with the amount of people. The sooner the substations are upgraded the better.
Sam

Sent from my ONEPLUS A3003 using Tapatalk

Don't hold your breath, all trams are accounted for and no more are currently on order.

 

[edwin_m]

The turnback on the Bury line will be at Crumpsall. I'm not aware of any plan to convert the remaining singles north of there to doubles.

 

[nerd]

The turnback on the Bury line will be at Crumpsall. I'm not aware of any plan to convert the remaining singles north of there to doubles.

If and when the tram-train proposals from Marple into Piccadilly go ahead, then the expectation was that it would comprise 10 services per hour, with 5 each running though to Altrincham and Bury respectively - hence displacing the current Alty-Picc and Bury-Picc single M5000 services. The likelihood is that the LRV units for such services would represent a 'next-generation' of Metrolink stock, tram-train compatible and configured as equivalents of doubled M5000s.

 

[edwin_m]

If and when the tram-train proposals from Marple into Piccadilly go ahead, then the expectation was that it would comprise 10 services per hour, with 5 each running though to Altrincham and Bury respectively - hence displacing the current Alty-Picc and Bury-Picc single M5000 services. The likelihood is that the LRV units for such services would represent a 'next-generation' of Metrolink stock, tram-train compatible and configured as equivalents of doubled M5000s.

Yes. My expectation is that having ordered enough trams to cover their foreseeable needs (Trafford won't be open for at least a couple of years) they will wait to see if tram-train is happening before ordering any more. By then there will be enough growth that the displaced M5000s will be needed on other routes.

 

[nerd]

Yes. My expectation is that having ordered enough trams to cover their foreseeable needs (Trafford won't be open for at least a couple of years) they will wait to see if tram-train is happening before ordering any more. By then there will be enough growth that the displaced M5000s will be needed on other routes.

Broadly yes edwin. In June GMCA included a review of tram capacity in its action list for 2017-21; with the option of a additional tram order of eight LRVs to enable the Altrincham-Piccadilly service to be run with doubles. It had been thought that these additional trams might consist of extra M5000 trams added onto the end of the 120 production run - which didn't happen. But otherwise, it could be that an additional order could herald a 'trial' initial batch of its next generation fleet; maybe in advance of any firm decisions from the Sheffield tram-train pilot. Counterpart to the manner in which the original eight tram order for doubling Altrincham-Bury services eventually morphed into a complete fleet replacement, once the qualities of the new stock (and deficiencies of the old T68s) became apparent.

 

[northwichcat]

If and when the tram-train proposals from Marple into Piccadilly go ahead, then the expectation was that it would comprise 10 services per hour, with 5 each running though to Altrincham and Bury respectively - hence displacing the current Alty-Picc and Bury-Picc single M5000 services. The likelihood is that the LRV units for such services would represent a 'next-generation' of Metrolink stock, tram-train compatible and configured as equivalents of doubled M5000s.

I thought they envisaged using only tram-trains to Altrincham if Marple tram-train gets the go ahead in the hope they could eliminate the single track bottleneck through Navigation Road. However, Stockport to Chester is now on the list of potential AC electrification schemes so if Metrolink want to do that the tram-trains may have to be dual-voltage or able to run between Timperley and Altrincham and back with the pantograph down.

 

[snowball]

However, Stockport to Chester is now on the list of potential AC electrification schemes so if Metrolink want to do that the tram-trains may have to be dual-voltage or able to run between Timperley and Altrincham and back with the pantograph down.

Surely any future Metrolink tram-trains would be dual voltage anyway. It doesn't seem very likely that they would have diesel engines, and it doesn't seem very likely that they would be 750V DC only.

 

[rebmcr]

If and when the tram-train proposals from Marple into Piccadilly go ahead, then the expectation was that it would comprise 10 services per hour, with 5 each running though to Altrincham and Bury respectively - hence displacing the current Alty-Picc and Bury-Picc single M5000 services. The likelihood is that the LRV units for such services would represent a 'next-generation' of Metrolink stock, tram-train compatible and configured as equivalents of doubled M5000s.

I thought they envisaged using only tram-trains to Altrincham if Marple tram-train gets the go ahead in the hope they could eliminate the single track bottleneck through Navigation Road. However, Stockport to Chester is now on the list of potential AC electrification schemes so if Metrolink want to do that the tram-trains may have to be dual-voltage or able to run between Timperley and Altrincham and back with the pantograph down.

Surely any future Metrolink tram-trains would be dual voltage anyway. It doesn't seem very likely that they would have diesel engines, and it doesn't seem very likely that they would be 750V DC only.

I'm fairly sure jcollins was implying an onboard battery to bridge the 'gap', recharged from the OHLE north of Timperley.

 

[nerd]

I thought they envisaged using only tram-trains to Altrincham if Marple tram-train gets the go ahead in the hope they could eliminate the single track bottleneck through Navigation Road. However, Stockport to Chester is now on the list of potential AC electrification schemes so if Metrolink want to do that the tram-trains may have to be dual-voltage or able to run between Timperley and Altrincham and back with the pantograph down.

Not my recollection jc; though there have been so many proposals for tram-train solutions around here, that I'm not at all sure which are considered still potentially doable.

But my impression of the current state of play, is that there is considered to be no essential problem with the single track through Navigation Road, so long as Metrolink services are running no more than 10 services per hour. So, if the 5 tph Altrincham-Piccadilly services are converted to run through to Marple as tram-train, there is no need for them to share space with Network Rail services through Navigation Road.

However, if tram-train services were to run from Altrincham to Stockport Interchange, and on to Reddish etc (as has also been suggested) then the bottleneck would need sorting to allow the extra Metrolink capacity.

But that begs the question; although there appears to be serious considertation being given to an orbital tram-train route from Stalybridge to the Airport through Stockport Interchange, taking those services further to Altrincham looks more problematic. So my expectation is that there will be tram-train services from Stockport westwards, but only as far as the Airport; and accordingly no need to remove the Navigation Road single working, even if some of the Metrolink services using it are formed from tram-train LRVs.

 

[northwichcat]

Not my recollection jc; though there have been so many proposals for tram-train solutions around here, that I'm not at all sure which are considered still potentially doable.

But my impression of the current state of play, is that there is considered to be no essential problem with the single track through Navigation Road, so long as Metrolink services are running no more than 10 services per hour. So, if the 5 tph Altrincham-Piccadilly services are converted to run through to Marple as tram-train, there is no need for them to share space with Network Rail services through Navigation Road.

However, if tram-train services were to run from Altrincham to Stockport Interchange, and on to Reddish etc (as has also been suggested) then the bottleneck would need sorting to allow the extra Metrolink capacity.

But that begs the question; although there appears to be serious considertation being given to an orbital tram-train route from Stalybridge to the Airport through Stockport Interchange, taking those services further to Altrincham looks more problematic. So my expectation is that there will be tram-train services from Stockport westwards, but only as far as the Airport; and accordingly no need to remove the Navigation Road single working, even if some of the Metrolink services using it are formed from tram-train LRVs.

The latest report (from late 2013) seems to have disappeared with the reworking of the PTE's websites. However, I still have a copy saved locally on my computer where they looked at four tram-train options involving Altrincham:
1. 10 tram-trains per hour to Altrincham
2. 10 tram-trains per hour to Altrincham with alternate ones continuing to Hale
3. 12 tram-trains per hour to Altrincham 6 continuing to Hale and 3 continuing to Knutsford
4. 5 tram-trains per hour between Altrincham and Stockport

Options 2, 3 and 4 were dismissed as low/poor value for money at the current time but they could be re-explored in the future.

Under Altrincham they said

The Altrincham route would involve tram-train operation of the existing Manchester – Altrincham Metrolink service on the section of route through Navigation Road Station, where heavy-rail and Metrolink services currently run on parallel single-line routes, causing a bottleneck on the Metrolink network.

The cost-benefit case for tram-train operation through this section of double track is only moderate. However, there could be as yet unquantified benefits in the form of increased flexibility of operation for the Metrolink network as a whole through unblocking the present bottleneck at Navigation Road (see “Metrolink network opportunities created” in Appendix 2).

Under Marple they said

Develop as a potential first full Tram-train line in Greater Manchester, possibly as part of a Phase 1 network comprising Marple and Altrincham.

 

[WatcherZero]

The concepts have moved on a bit to focus on expanding the network around the Altrincham/Airport/Stockport area with the opportunity HS2 provides to get some government cash to support its integration in to existing transport networks. Same way Birmingham then used it to get support for a extension of street running.

 

[edwin_m]

The concepts have moved on a bit to focus on expanding the network around the Altrincham/Airport/Stockport area with the opportunity HS2 provides to get some government cash to support its integration in to existing transport networks. Same way Birmingham then used it to get support for a extension of street running.

Yes, there is real potential to give the Airport HS2 station much wider public transport connectivity across south Manchester, also benefitting the Airport itself and the existing and planned employment areas surrounding it. The unbuilt Metrolink route via Wythenshawe Hospital (for which I think TfGM have powers) runs very close to the HS2 site and suitable connections at Baguley would allow through running to by tram-trains to Stockport and perhaps even Warrington via the Carrington line.

 

[Greybeard33]

The unbuilt Metrolink route via Wythenshawe Hospital (for which I think TfGM have powers) runs very close to the HS2 site and suitable connections at Baguley would allow through running to by tram-trains to Stockport and perhaps even Warrington via the Carrington line.

Tram-trains from Manchester Airport to Warrington Central, crossing the Ship Canal on the Cadishead Viaduct, which BR closed over 30 years ago as beyond economic repair, and which has been quietly rusting away ever since? In competition with the existing hourly ATW service from the Airport direct to Warrington Bank Quay, with a 50 minute journey time? Good luck with the business case!

But is this not straying somewhat off topic?

 

[edwin_m]

Tram-trains from Manchester Airport to Warrington Central, crossing the Ship Canal on the Cadishead Viaduct, which BR closed over 30 years ago as beyond economic repair, and which has been quietly rusting away ever since? In competition with the existing hourly ATW service from the Airport direct to Warrington Bank Quay, with a 50 minute journey time? Good luck with the business case!

But is this not straying somewhat off topic?

It could possibly turn northwards at Carrington to join the existing line somewhere around Irlam, therefore not using the Cadishead viaduct. Alternatively the viaduct could be OK for lighter tram-trains. However I wasn't involved in that feasibility study so can't say what it concluded.

 

[Chester1]

Are there any plans to quad track the line between Cornbrook and Deansgate-Castlefield? I am surprised this is not part of the 2CC which only removes half the bottleneck. There is a disused viaduct running right next to the metro tracks for the entire route and using it would reduce the bottleneck to just Deansgate to St Peters square.