Lengthening Birmingham - Stansted Services

[jfowkes]

Hi all,

I can find some previous discussion around this already, but nothing that in depth.

I'm wondering what would be required to increase the length of the cross country Birmingham-Stansted services? In terms of platform extensions, moving signals, etc.

How many coaches could you add now, with no or very little infrastructure changes?
As you increase train length, what are the extra changes you'd need to make to support that?

For the purposes of this discussion I'm only interested in increasing train length, not service frequency.

 

[O L Leigh]

The maximum today is 4 cars. The primary issue is platform usage at the airport itself, as the bay platform used by XC services cannot accommodate more than 4. This would be the main restriction, as Cl170s have door deselect which means that intermediate platforms would not be an issue. There may be some re-allocation of platform usage, but Stansted is classed as a sub-surface station with restrictions on platforming diesel traction.

With the exception of the “major” stations on the route, most stations have 4 car platforms with one or two exceptions (3 at Stamford and 2 at Whittlesey and Manea). Doubled units, especially 5 car 2+3 formations, may be a problem because at some platforms you may find one entire unit not platformed, which could be an issue with passenger boarding/alighting and disabled access.

 

[jfowkes]

Thanks for all that!

There may be some re-allocation of platform usage, but Stansted is classed as a sub-surface station with restrictions on platforming diesel traction.

Would that be the case at New Street too?

 

[O L Leigh]

Would that be the case at New Street too?

I guess that there is some legacy arrangement there. Certainly there’s not the same risk of setting off the fire alarms as there is at Stansted, which has [ahem] “hilarious consequences”. Certainly there are no local instructions relating to diesel traction at New Street as there is at Stansted.

 

[Class 170101]

The maximum today is 4 cars. The primary issue is platform usage at the airport itself, as the bay platform used by XC services cannot accommodate more than 4. This would be the main restriction, as Cl170s have door deselect which means that intermediate platforms would not be an issue. There may be some re-allocation of platform usage, but Stansted is classed as a sub-surface station with restrictions on platforming diesel traction.

Could solve that issue with Bi-mode traction.

With the exception of the “major” stations on the route, most stations have 4 car platforms with one or two exceptions (3 at Stamford and 2 at Whittlesey and Manea). Doubled units, especially 5 car 2+3 formations, may be a problem because at some platforms you may find one entire unit not platformed, which could be an issue with passenger boarding/alighting and disabled access.

You could argue that Whittlesea and Manea need not be served by XC if GA were able to run an hourly service on the route betwee Ipswich and Peterborough.

 

[O L Leigh]

Could solve that issue with Bi-mode traction.

Not without also looking at platform utilisations at Stansted. There may only be 2tph frequency on the Stansted Express at the moment, but it may yet return to 4tph which would mean that the XC service still needs to use the bay platform. Bear in mind that, as it stands now, stock for the GA Norwich service is at the airport at the same time as the stock for the XC Birmingham service. The use of bi-modal stock does not increase the length of the bay platform.

You could argue that Whittlesea and Manea need not be served by XC if GA were able to run an hourly service on the route betwee Ipswich and Peterborough.

Perhaps. My understanding of the need to stop XC services is to satisfy peak loadings from Peterborough, so it may simply have more to do with timing of the services along that section at that time of day. The XC departure is 1716 while the next GA is 1750, so it’s not like there’s a huge gap.

 

[class397tpe]

Unless I'm missing something it doesn't seem like a platform extension at Stanstead would be too complex at all - the tracks of platform 3 and 2 remain equally spaced for a good 70 metres after the platform ends, so an extension to allow 6 cars wouldn't require reconfiguration of the layout. If access to platform 1 was required while a train was in Platform 3, I think you could still extend it by a good 30 metres to allow 5 car trains. Of course, you'd need to find the money from somewhere.

 

[O L Leigh]

Unless I'm missing something it doesn't seem like a platform extension at Stanstead would be too complex at all - the tracks of platform 3 and 2 remain equally spaced for a good 70 metres after the platform ends, so an extension to allow 6 cars wouldn't require reconfiguration of the layout. If access to platform 1 was required while a train was in Platform 3, I think you could still extend it by a good 30 metres to allow 5 car trains. Of course, you'd need to find the money from somewhere.

That may mean an alteration to the signalling arrangements, as the signal currently is less than one additional car length off the end of the platform. Any change would mean a very short overlap heading towards a point of conflict. The bay has already been lengthened once out to it’s current length.

However, I would have to repeat what I said about the problems of running 5 car double sets. Unless you’re going to opt for new stock as well, Stamford needs to be lengthened also to a minimum of 4 cars while those services stopping at Whittlesey and Manea would continue to be diagrammed as a single unit.

 

[D365]

It's a safe bet that Birmingham-Stansted trains won't ever exceed four cars in length.

 

[Class 170101]

Could solve that issue with Bi-mode traction.

Sorry I was referring to platforming for traction type. Bi-modes can use the 'underground' platforms.

Not without also looking at platform utilisations at Stansted. There may only be 2tph frequency on the Stansted Express at the moment, but it may yet return to 4tph which would mean that the XC service still needs to use the bay platform. Bear in mind that, as it stands now, stock for the GA Norwich service is at the airport at the same time as the stock for the XC Birmingham service. The use of bi-modal stock does not increase the length of the bay platform.

The Norwich is unlikely to change due to the various single line constraints at Trowse, Ely North Jn, Stansted approaches nevermind everything else.

No chance of 4tph on LST to SSD this side of December TT change, looking at RTT and knowing the DfT probably beyond.

Unless I'm missing something it doesn't seem like a platform extension at Stanstead would be too complex at all - the tracks of platform 3 and 2 remain equally spaced for a good 70 metres after the platform ends, so an extension to allow 6 cars wouldn't require reconfiguration of the layout. If access to platform 1 was required while a train was in Platform 3, I think you could still extend it by a good 30 metres to allow 5 car trains. Of course, you'd need to find the money from somewhere.

That may mean an alteration to the signalling arrangements, as the signal currently is less than one additional car length off the end of the platform. Any change would mean a very short overlap heading towards a point of conflict. The bay has already been lengthened once out to it’s current length.

Why must it be extended out from Platform 2? Can it not be extended at the buffer stop end, further into the building?

 

[O L Leigh]

Sorry I was referring to platforming for traction type. Bi-modes can use the 'underground' platforms.

Yes of course. But as I mentioned, saying that it’s possible is a whole different thing from it being realistic.

This touches on platform utilisation, as I mentioned before. If XC use the longer sub-surface platforms they end up sharing with the GA services with all that entails, and you reduce the station capacity by one platform.

But even if you swap around the Norwich and Birmingham services you don’t actually make any difference to station capacity. There is only one platform long enough to permit sharing with the StanEx Cl745 units, and there isn’t space to share with anything longer than a 4 car Cl755. Allowing XC to platform share won’t allow for lengthening their services.

No chance of 4tph on LST to SSD this side of December TT change, looking at RTT and knowing the DfT probably beyond.

Yes, maybe. But if you change anything with either the Norwich or Birmingham services you commit yourself to never having more than 2tph on the Stansted Express. Whether this comes to be the case will remain to be seen.

Why must it be extended out from Platform 2? Can it not be extended at the buffer stop end, further into the building?

Because then you’re putting diesel traction under the roof, which is not permitted. If you cut back the platform to move the blocks you also have to make a similarly sizeable cut into the terminal building above.

 

[jfowkes]

It's a safe bet that Birmingham-Stansted trains won't ever exceed four cars in length.

Why is that? There appears to be demand, they're often full and standing.

 

[Class 170101]

Because then you’re putting diesel traction under the roof, which is not permitted. If you cut back the platform to move the blocks you also have to make a similarly sizeable cut into the terminal building above.

In that case maybe 3 cars to Stansted Airport to / from Cambridge....

Why is that? There appears to be demand, they're often full and standing.

and pick up / detach another three carriages at Cambridge for onward operation to / from New Street.

 

[O L Leigh]

In that case maybe 3 cars to Stansted Airport to / from Cambridge....

and pick up / detach another three carriages at Cambridge for onward operation to / from New Street.

No need to complicate matters in this way. The bay at Stansted is the same length as most other platforms on the route, so it’s entirely possible to run the service at 4 cars throughout except for those stopping at Whittlesey and Manea.

 

[D365]

Why is that? There appears to be demand, they're often full and standing.

Because the majority of platforms are not long enough.

 

[O L Leigh]

Because the majority of platforms are not long enough.

And also because any crush loading is not universally felt across the whole route. It’s often where the service duplicates others (e.g. Cambridge to Ely).

 

[dk1]

Ironically Norwich-Stansted BMUs operate as normal into platforms 1 & 3 at the airport even in diesel mode. There is no restriction if their pan/pans are isolated. I presume the Cambridge driver just shuts the engines down asap on arrival.

 

[O L Leigh]

Has that happened?

 

[dk1]

Has that happened?

Are you replying to me?

 

[O L Leigh]

Um, yes of course.

 

[dk1]

Um, yes of course.

Um, wasn’t obvious.

Yes, it happens all the time.

 

[O L Leigh]

Apologies. As there were no other posts appearing in between I thought it would have been clear that the thread was continuing in a linear manner.

Yes the local instructions are to shut down diesel units immediately on arrival and only start them up again as late as possible prior to departure due to the aforementioned fire alarms. However, in all my years of going to Stansted I have only ever twice seen CT/XC DMUs on P1 or P3, and on one of those occasions the unit was still outside away from the roof. Your newer Cl755s certainly seem to have a cleaner exhaust than a Cl170 so perhaps they are tolerated under the roof more than the XC services. Also, because the XC unit would be sat for anything up to 45 minutes, there's a good chance it would lose main air pressure and require running up for longer prior to departure in order to recharge.

The fire alarms at the airport really are no laughing matter. If they are triggered they cause chaos and massive disruption to the entire airport operation.

 

[dk1]

Apologies. As there were no other posts appearing in between I thought it would have been clear that the thread was continuing in a linear manner.

Yes the local instructions are to shut down diesel units immediately on arrival and only start them up again as late as possible prior to departure due to the aforementioned fire alarms. However, in all my years of going to Stansted I have only ever twice seen CT/XC DMUs on P1 or P3, and on one of those occasions the unit was still outside away from the roof. Your newer Cl755s certainly seem to have a cleaner exhaust than a Cl170 so perhaps they are tolerated under the roof more than the XC services. Also, because the XC unit would be sat for anything up to 45 minutes, there's a good chance it would lose main air pressure and require running up for longer prior to departure in order to recharge.

The fire alarms at the airport really are no laughing matter. If they are triggered they cause chaos and massive disruption to the entire airport operation.

The first time I took a diesel only 755 to Cambridge in early 2020 after they where extended to the airport I rang control as I too only thought they could use 1 & 3 on electric. I was advised it would be fine & have taken many trains with pans isolated since.

 

[Bald Rick]

Unless I'm missing something it doesn't seem like a platform extension at Stanstead would be too complex at all - the tracks of platform 3 and 2 remain equally spaced for a good 70 metres after the platform ends, so an extension to allow 6 cars wouldn't require reconfiguration of the layout. If access to platform 1 was required while a train was in Platform 3, I think you could still extend it by a good 30 metres to allow 5 car trains. Of course, you'd need to find the money from somewhere.

It is complex. The overlaps for the signalling are already at the minimum permitted. To provide an extension at the London end means remodelling all the tracks and resignalling.

Why must it be extended out from Platform 2? Can it not be extended at the buffer stop end, further into the building?

Immediately behind the buffer stops is one of the main support columns for the terminal building. So yes you could extend that way, but you’d be demolishing part of the terminal to do so.