4tph to bristol, how?

[TheWalrus]

Having read the GW franchise consultation, they seem quite keen on having 4tph iep services from london-bristol; 2 via parkway, 2 via bath. My question is how are they expecting to fit in all these additional paths out of padd, especially in the peaks! It will be at full line capacity what will happen when we cant fit in any more paths?

 

[heart-of-wessex]

Can't see the issue....do you mean 4tph on what's on top already??

There is currently 4tph at the moment anyway, 2 towards bristol via bath and 2 towards cardiff (one terminates there and the other goes to Swansea, in the daytime) unless it's a Saturday where it's around 3tph, but fits in nicely with the schedule at the moment

 

[anthony263]

There was talk of the heathrow express services being withdrawn something I agree with especially when crossrail starts and perhaps there are some semi fast services to/from Heathrow.

 

[Anonywave]

The Heathrow expresses are probably not going to be withdrawn but I presume that the Heathrow connect services (the stopping ones) would become the crossrail services.

 

[TEW]

The RUS suggests withdrawal of Heathrow Express services from the fast lines. It is hard to see how 2 extra paths will be found in the peaks otherwise.

 

[The Planner]

Nothing stopping you doing a lot more out of Padd on the mains than there is now, 2½ minute headways to Airport Jn and 3 minutes to Reading, it just isn't an optimal timetable as it is at the mo.

 

[150222]

...Of course then northern could have the 332's.

 

[TheWalrus]

So what is going to happen to heathrow express? Tbh it would provide relief to the fast lines if it went.
--- old post above --- --- new post below ---

Can't see the issue....do you mean 4tph on what's on top already??

There is currently 4tph at the moment anyway, 2 towards bristol via bath and 2 towards cardiff (one terminates there and the other goes to Swansea, in the daytime) unless it's a Saturday where it's around 3tph, but fits in nicely with the schedule at the moment

I mean additional 2tph via parkway.

 

[anthony263]

...Of course then northern could have the 332's.

Pity they are not dual voltage and the line between Bath & Southampton isnt electrified they would be brilliant for the Cardiff - Portsmouth Harbour service.

Could use them on the Transpenine express network when the routes are electrified

 

[Zoe]

I wold have thought you'd get some extra capacity once ERTMS in installed.

 

[Nym]

I wold have thought you'd get some extra capacity once ERTMS in installed.

They will indeed, ERTMS uses dynamic moving blocks in some of it's implementations, but ERTMS is only a commuinications standard, not a blocking or pathing standard.

 

[Zoe]

They will indeed, ERTMS uses dynamic moving blocks in some of it's implementations, but ERTMS is only a commuinications standard, not a blocking or pathing standard.

It's not just a communications standard, it also includes signalling and train protection.

 

[Nym]

But you can implement ERTMS on standard block signals that currently use TWPS and AWS without implementing any other systems atop of it for moving block signalling, such as ERTMS0 or ERTMS1...

 

[Zoe]

But you can implement ERTMS on standard block signals that currently use TWPS and AWS without implementing any other systems atop of it for moving block signalling, such as ERTMS0 or ERTMS1...

Well as far as I know the plan is to install level 2 not level 3 (moving block) but even at level 2 you don't need lineside signals.

 

[Nym]

The plan is currently for Level 2, that will implement a TVM430 style clearance block system, similar to our current coloured light / ATP combination, where a target speed is given at the beginning of each block, taking into account unit performance, timetable, and other units running on the same line.

 

[Zoe]

The plan is currently for Level 2, that will implement a TVM430 style clearance block system, similar to our current coloured light / ATP combination, where a target speed is given at the beginning of each block, taking into account unit performance, timetable, and other units running on the same line.

This could still offer some increase in capacity although not as significant as with moving block.

 

[Nym]

That IS re-signalling, once the ERTMS interface blocks are in place, and the track circuits / axle counters in place, you can implement whatever singalling regieime you like...

 

[Zoe]

That IS re-signalling, once the ERTMS interface blocks are in place, and the track circuits / axle counters in place, you can implement whatever singalling regieime you like...

So this can be used to get capacity on the GWML then.

 

[Nym]

It could indeed, if the track was suitable it could also be used for 125mph+ running.

The major increases in capacity can be gained by making sure trains don't stop at red signals, and by knowing, since ERTMS will know the position of every unit on the network, it is possible to ensure that headways can be maintained at better speeds, and also better take into account braking performance of each unit, meaning shorter headways.

Homoganisation and higher performance stock will help too.

 

[The Planner]

Depends on where the blocks are placed, and there is no way you could convincingly use ERTMS on a terminal station as big as the London ones.

 

[Zoe]

Depends on where the blocks are placed, and there is no way you could convincingly use ERTMS on a terminal station as big as the London ones.

Why not? I would have thought Paddington would be included in the GWML scheme. The trains would simply be given authority to move between block sections.

 

[Nym]

The_Planner: Not in it's current implementations, but the basic system it'self is ultimately expandable as far as you could want it to be.

If you take the ERTMS comms standards and write a better set of interlocking codes and checks for it, and then intergrate it into platform buttons / signage for dispatchers, you can implement whatever the hell you want.

You could even put the close doors buttons for units on the platforms if you really wanted, ERTMS would support that. It would also support the retention of RA commands from dispatchers, CD Commands, etc. etc. All you need to do is implement the communications atop the current interface provided by ERTMS and GSM-R.

 

[Bald Rick]

ERTMS cannot improve capacity at 'fixed' points on the network, e.g. Junction clearance margins, station dwell times, level crossings etc.

Regular, correctly spaced 4 aspect signalling is perfectly capable of running 24 tph at up to 125mph, as is done on the GEML every peak (albeit not at 125mph sadly!)

To return to the OP, perhaps the question to pose is not so much 'how do you fit in 2 additional Bristol trains' but 'if there are 2 spare fast paths out of Paddington, where should they go?'

With an eye on other threads on the forum, the answer isn't Liverpool

 

[Waverley125]

to be honest, i think 4tph to Temple Meads would be slightly ridiculous, but 3tph to Parkway, two on to Wales and one to Temple Meads wouldn't be too ridiculous (assuming 2tph running via Bath)

so you might well have, say

Paddington-Bristol (stopper): Reading, Didcot Parkway, Swindon, Chippenham, Bath Spa, Keynsham, Bristol Temple Meads

Paddington-Bristol (Semi): Reading, Swindon, Chippenham, Bath Spa, Bristol Temple Meads

Paddington-Bristol (Fast): Reading, Bristol Parkway, Bristol Temple Meads

Paddington-Cardiff Central (Semi): Reading, Didcot Parkway, Swindon, Bristol Parkway, Newport, Cardiff Central

Paddington-Swansea (Fast): Reading, Swindon, Newport, Cardiff Central, Bridgend, Port Talbot Parkway, Neath, Swansea

 

[tbtc]

To return to the OP, perhaps the question to pose is not so much 'how do you fit in 2 additional Bristol trains' but 'if there are 2 spare fast paths out of Paddington, where should they go?'

With an eye on other threads on the forum, the answer isn't Liverpool

That's a good question (and presumably the answer isn't Blackpool either?)...

Four/hour to Bristol presumably means no capacity for an increase in the bi-hourly Gloucester/Cheltenham service (which many on here want electrifying).

You'd have...

• 4x Heathrow Express
• 4x Oxford (two fast, two slow)
• 0.5x Cheltenham/Gloucester
• 2x Wales (one to Swansea, one just to Cardiff)
• 2x Bristol (via Bath)
• 1x West Country
• 1x Newbury
• 2x Reading "semi fasts" (the xx.12 and xx.42 departures - since the current Crossrail plans don't extend beyond Maidenhead, you'd have to slow down another service to stop at Twyford if you chopped these?)

...plus 2x Bristol (via Bristol Parkway). Eighteen/nineteen an hour sounds possible (easier if you slow down another service to pick up the Twyford stops in the XX.12/XX.42 - so that Crossrail can replace the remainder of that service as far as Maidenhead).

(please correct me if my maths are wrong)

 

[Zoe]

Four/hour to Bristol presumably means no capacity for an increase in the bi-hourly Gloucester/Cheltenham service (which many on here want electrifying).

If there's a path one hour then what takes that path the other hour? Also you could in theory split one of the Bristol service at Swindon with half running to Bristol and the other to Cheltenham.

 

[tbtc]

If there's a path one hour then what takes that path the other hour? Also you could in theory split one of the Bristol service at Swindon with half running to Bristol and the other to Cheltenham.

I don't know, and I don't know what takes the path half an hour opposite the Cheltenham service (since all other services through Didcot run half hourly).

But with six/hour from London to Bristol/Cardiff via Swindon, I don't think there will be a lot of space for any additional Cheltenham services.

Maybe the plan is to cut the daytime Cheltenham service at Swindon? Dunno...

 

[Zoe]

But with six/hour from London to Bristol/Cardiff via Swindon, I don't think there will be a lot of space for any additional Cheltenham services.

As I say, you could split one of the Bristol services at Swindon.

 

[tbtc]

It was the Cheltenham service that I was referring to.

As I say, you could split one of the Bristol services at Swindon.

Yes, i was meaning that I don't know what the XX.46 path from Reading (towards Swindon) is used for.

For example, at the moment all the services from Reading towards Didcot/ Oxford/ Swindon are half hourly apart from this oddity.

Not sure about joining/splitting at Swindon as you'd have to have a fairly short train for Bristol to allow it to work in multiple (e.g. nothing like the HST length that Bristol passengers currently enjoy)

 

[TheWalrus]

So would all fast services need to be non stop to reading to increase line capacity?