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Midland Mainline (South) capacity issues

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londonmidland

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Primarily focusing on the Bedford to London St Pancras section of the line, it is quite obvious there are some pathing and capacity issues.

I am currently on an East Midlands Trains ‘fast’ service to London St Pancras, 1C42 to be specific. Everything appears to be fine until we started approaching Luton. 9T37 Bedford to Brighton was put on the ‘fasts’ from Luton and calls at Luton Airport Parkway, Harpenden, before going onto the ‘slows’ before St Albans.

Now, it isn’t too much of a problem as we didn’t pick up too much of a delay but it seems an ever increasing occurrence that Thameslink get routed on to the fasts in front of ‘on time’ EMT services. Not much of an issue for 222’s with their good braking and rapid acceleration but for HSTs you can pick up quite a few minutes from the constant braking a slow acceleration.

Is it, to put it in simple terms, trying to cram too many trains in at once and not enough lines?
 
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yorkie

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Yes this is a known issue, and is the reason why some EMT services have had to have additional allowance put into their schedules, and in turn has resulted in additional trains being required. This is the reason why they are using ex-Grand Central HSTs.
 

Hairy Bear

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Get used to it. Happens day in ,day out to us. Regually take 4 to 5 mins out of us, irrespective of whether were on time or not. They have priority over us. Now the norm.
 

A0wen

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Primarily focusing on the Bedford to London St Pancras section of the line, it is quite obvious there are some pathing and capacity issues.

I am currently on an East Midlands Trains ‘fast’ service to London St Pancras, 1C42 to be specific. Everything appears to be fine until we started approaching Luton. 9T37 Bedford to Brighton was put on the ‘fasts’ from Luton and calls at Luton Airport Parkway, Harpenden, before going onto the ‘slows’ before St Albans.

Now, it isn’t too much of a problem as we didn’t pick up too much of a delay but it seems an ever increasing occurrence that Thameslink get routed on to the fasts in front of ‘on time’ EMT services. Not much of an issue for 222’s with their good braking and rapid acceleration but for HSTs you can pick up quite a few minutes from the constant braking a slow acceleration.

Is it, to put it in simple terms, trying to cram too many trains in at once and not enough lines?

In some ways it's a shame the MML is paired by use, rather than as the ECML by direction.

That way it's easier to move a train from the slow to the fast to overtake a slower train and back to the slow - with the MML's pairing it means blocking the one of the tracks in the opposite direction.
 

HowardGWR

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In some ways it's a shame the MML is paired by use, rather than as the ECML by direction.

That way it's easier to move a train from the slow to the fast to overtake a slower train and back to the slow - with the MML's pairing it means blocking the one of the tracks in the opposite direction.
In what ways isn't it a shame? Not knowing the line well, I am interested in your view.
 

Dr Hoo

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In what ways isn't it a shame? Not knowing the line well, I am interested in your view.
Well, the ‘paired by use/speed configuration’ allows centre turn backs at St Albans, Luton and Bedford, serves the various stone terminals from the slow lines and concentrates depot moves at Cricklewood and Bedford to/from the slows.
As has been argued many times on this forum, unless you spend many millions on flyovers, additional platforms, etc. neither pairing configuration is ideal.
 

DanDaDriver

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Well, the ‘paired by use/speed configuration’ allows centre turn backs at St Albans, Luton and Bedford, serves the various stone terminals from the slow lines and concentrates depot moves at Cricklewood and Bedford to/from the slows.
As has been argued many times on this forum, unless you spend many millions on flyovers, additional platforms, etc. neither pairing configuration is ideal.

Speeding up the junctions would help. Mostly 40mph south Bedford. Those thameslinks can shift, but waiting for one to cross over, particularly if you get double-blocked for Harpenden for example, really does slow you down.

Whether the cost/benefit would stack up is another matter.
 

Bald Rick

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Primarily focusing on the Bedford to London St Pancras section of the line, it is quite obvious there are some pathing and capacity issues.

I am currently on an East Midlands Trains ‘fast’ service to London St Pancras, 1C42 to be specific. Everything appears to be fine until we started approaching Luton. 9T37 Bedford to Brighton was put on the ‘fasts’ from Luton and calls at Luton Airport Parkway, Harpenden, before going onto the ‘slows’ before St Albans.

Now, it isn’t too much of a problem as we didn’t pick up too much of a delay but it seems an ever increasing occurrence that Thameslink get routed on to the fasts in front of ‘on time’ EMT services. Not much of an issue for 222’s with their good braking and rapid acceleration but for HSTs you can pick up quite a few minutes from the constant braking a slow acceleration.

Is it, to put it in simple terms, trying to cram too many trains in at once and not enough lines?

9T37 is booked up slow Bedford to Radlett, so for some reason it must have been put across to the up fast at Leagrave (an infrequent move) to get out of the way of something in the Luton area. Knocked your train for a couple of minutes. It’s not a planned thing. The signaller was evidently on the ball as you went back slow line at Harpenden which enabled you to overtake.

Speeding up the junctions would help. Mostly 40mph south Bedford. Those thameslinks can shift, but waiting for one to cross over, particularly if you get double-blocked for Harpenden for example, really does slow you down.

Whether the cost/benefit would stack up is another matter.

It’s been looked at. Unfortunately the junctions are generally located perfectly in signal sections, so to make them higher speed they would have to stretch over two sections, or have certain crossing routes removed. Or both. Then it starts getting very expensive in signalling as well as the track and OLE.

Also there isn’t much straight track where they can go!
 

DanDaDriver

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It’s been looked at. Unfortunately the junctions are generally located perfectly in signal sections, so to make them higher speed they would have to stretch over two sections, or have certain crossing routes removed. Or both. Then it starts getting very expensive in signalling as well as the track and OLE.

Also there isn’t much straight track where they can go!

That makes sense.

On Saturdays when there’s fewer Thamselinks and Northen are on strike and you’re making excellent time under greens, you really get a sense of just how crowded the railway actually is.
 

mr_jrt

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It'd be nice to be able to have the land required to have the fasts on the outside - unfortunately the land required to ease the curvature (you don't want to be bowing out sharply at every station!) would be just north and south of stations, so probably among the most constrained (and thus, expensive) areas. That said, when switching from paired by use to paired by direction you only need said land on one side of the formation as the outermost fast line stays as-is.

On the upside, you would gain, along with the inherent ability of paired by-direction to move between fast and slow without conflicts and have easy cross-platform interchanges between fast and slow services, the ability to only require a single centre island platform for local stations - reducing infrastructure requirements (abet you would always need a bridge or subway to reach it!). Also means you can add and remove centre turnbacks wherever you like easily as traffic patterns ebb and flow. It's like benefits of paired by use plus a bit more. Junctions are the main issue as you always need to cross the fasts. You already have this on one side with paired by use, but this arrangement pretty much prevents you even contemplating a basic flat crossing for a branch.

Going the other way with the fasts in the middle like the ECML, you have no problems with the fasts as they always have the best alignment, and as junctions are more likely to be the slows at least one side will be conflict-free, but you will still require a single track flyover for one of them, and you will require a single track flyover (or diveunder) for every turnback, which is a big hindrance, though how often do these sorts of things change realistically?

I guess in short, in metro areas with frequent turnbacks fasts on the outside makes most sense, and outside of those fasts in the centre makes most sense. :)
 

Dr Hoo

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Access to freight terminals and depots is still a problem with 'slows in the middle/fasts on the outside'. There are at least six terminals on the 'slow' side of the MML, with proposals for more.
 

John Webb

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Access to freight terminals and depots is still a problem with 'slows in the middle/fasts on the outside'. There are at least six terminals on the 'slow' side of the MML, with proposals for more.
Including a fairly long-standing proposal for the terminal south of St Albans which is on the fast side of the line......
 

richieb1971

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Bedford to STP is going to get worse over the years to come. Huge housing developments everywhere, all priced to sell to Londoners or London commuters. Just in Bedford alone every new housing estate is made up of homes that cost £400k and above and that doesn't suit the economy of Bedford at all. All the sellers of these homes are promoting the THL railway links and EMT links as fast tracks to London and the easy access to Bedford Midland station when I go there to speak to them (I make a habit of bringing it up).

Lets not forget that it is NR that determines how trains run though. If a THL gets moved to the fast that is a choice made by them.

When I was in Japan I noticed that when I was on a semi fast, they used the stations extra platforms to park the train for 8-10 minutes to let a super fast go fast on the mainline, then my semi fast train would continue behind it on the fasts. Since you have stations like Luton at the halfway point I think the strategy could work there since Luton has an outside platform that I believe is connected at each end to the mainlines. I'm guessing these platforms are used for trains starting at Luton, but a jig around could alleviate some of that.

edit - Just thought, this is another problem caused by THL parking in platforms. MML stations really need sidings for that stuff. Bedford/Luton/St Albans at least.
 

londonmidland

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It's a bit ironic Network Rail upgraded sections of the MML for 125mph working, but increasingly we're seeing less use for it as 100mph EMU trains restrict this as any following 125mph capable trains are 'chasing yellows'.
 

Bald Rick

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Including a fairly long-standing proposal for the terminal south of St Albans which is on the fast side of the line......

I still don’t believe that will ever see a freight train, and probably not even a freight terminal.
 

Bald Rick

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edit - Just thought, this is another problem caused by THL parking in platforms. MML stations really need sidings for that stuff. Bedford/Luton/St Albans at least.

What, like the sidings at Bedford and St Albans?
 

richieb1971

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What, like the sidings at Bedford and St Albans?

Cant speak for at Alban's but bedford platforms are used to park trains reversing. I pass there every morning and if traffic is slow across bromham road bridge I see two or three trains parked in the through platforms. To date nobody seems to question thameslinks right to hold all the through platforms. If EWR went through there tomorrow it would mean giving up P1 almost completely. Let alone Corby EMT trains and freight.

Wouldn't surprise me if Thameslink hold p4 for periods when the ohle goes north.
 

Bald Rick

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Cant speak for at Alban's but bedford platforms are used to park trains reversing. I pass there every morning and if traffic is slow across bromham road bridge I see two or three trains parked in the through platforms. To date nobody seems to question thameslinks right to hold all the through platforms. If EWR went through there tomorrow it would mean giving up P1 almost completely. Let alone Corby EMT trains and freight.

Wouldn't surprise me if Thameslink hold p4 for periods when the ohle goes north.

There’s a reversing siding immediately north of St Albans between the slow lines.

The Thameslink trains aren’t ‘parked’, they are in service between duties; ie passengers getting off, new passengers getting on. Sometimes they are timetabled to be there for less than 10 minutes. There are lots of occasions in the timetable of trains being taken out of service there and immediately taken to the sidings to clear the platform.

It would surprise me, immensely, (to betting my mortgage levels) if Thameslink trains were ‘held’ in platform 4 between duties. Not least because there is no signalled route south from the platform. What is much more likely is that certain TL trains might terminate on plats 1, 2 or 3 and be shunted north to turn back on the down slow clear of WH638 subsidiary signal to clear the platform.
 

richieb1971

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Yes between duties. Anything from north using branch line parks north of Bedford sometimes 30 minutes. A year ago the cement and two oil trains regularly parked at red at kempston. This clogs a line and it's because thl have trains between duties.
 

twpsaesneg

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Yes between duties. Anything from north using branch line parks north of Bedford sometimes 30 minutes. A year ago the cement and two oil trains regularly parked at red at kempston. This clogs a line and it's because thl have trains between duties.
Bedford has an EMU reversing siding and the Down Passenger Loop to turn back trains without affecting the "main" lines, plus platforms 1 & 2 are bidirectionally signalled. The freight trains you see at Bedford North aren't waiting because they're in a traffic jam but will be waiting their very tight paths South. Certainly for the Radlett quarry and London Cement flows they have to run their booked path.

Luton has 5 platforms and trains turning back will generally use Platform 2 which is between the Up and Down Slow lines, thus leaving the through lines clear, though again platforms 1 to 3 are now all bidirectionally signalled so the signaller can work round a train using another platform if necessary.

St. Albans has a reversing siding to the north of the platforms which is again clear of the through lines.

If you could realign the fast lines through Harpenden and St Albans and provide a massive pair of dynamic loops to enable TL semi-fasts to serve the fast line platforms and for MMLE services to overtake on non-platform lines that would probably help, but sadly that's in the realms of fantasy given the geographic constraints and land prices.
 

Bald Rick

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If you could realign the fast lines through Harpenden and St Albans and provide a massive pair of dynamic loops to enable TL semi-fasts to serve the fast line platforms and for MMLE services to overtake on non-platform lines that would probably help, but sadly that's in the realms of fantasy given the geographic constraints and land prices.

Not half! The property costs for such a proposal would be getting on for half a billion!
 

edwin_m

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I still don’t believe that will ever see a freight train, and probably not even a freight terminal.
Just occurred to me that this is the exact optimum location where the Thameslink fasts ought to be crossing to/from the Slow lines, given that (ignoring the temporary Bedford fasts and some odd peak workings) they call all stations from St Albans northwards. I wonder if the freight terminal would be operationally a net benefit (assuming it got some rail traffic!) if its acess arrangements included a flyover that not only took the freights over the fasts but also allowed Thameslink to cross Fast/Slow without conflicting with moves in the other direction.
 

ChiefPlanner

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Just occurred to me that this is the exact optimum location where the Thameslink fasts ought to be crossing to/from the Slow lines, given that (ignoring the temporary Bedford fasts and some odd peak workings) they call all stations from St Albans northwards. I wonder if the freight terminal would be operationally a net benefit (assuming it got some rail traffic!) if its acess arrangements included a flyover that not only took the freights over the fasts but also allowed Thameslink to cross Fast/Slow without conflicting with moves in the other direction.

Should this "freight terminal" appear at Radlett (pause for prolonged and hollow laughter) , the artists impressions showed a dive under off the slow lines. A flyover , removing the carefully preserved view of the Abbey of St Alban , would not , go down well. It maybe be not St Pauls ,- but the skyline view is carefully preserved in all directions. Rightly so.

Anyway - options for extra trackage Radlett to Harpenden are basically complete not starters for reasons mentioned before.
 

Verulamius

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Just occurred to me that this is the exact optimum location where the Thameslink fasts ought to be crossing to/from the Slow lines, given that (ignoring the temporary Bedford fasts and some odd peak workings) they call all stations from St Albans northwards. I wonder if the freight terminal would be operationally a net benefit (assuming it got some rail traffic!) if its acess arrangements included a flyover that not only took the freights over the fasts but also allowed Thameslink to cross Fast/Slow without conflicting with moves in the other direction.

I would disagree. You should have a cross over north of St Albans once the St Albans terminators are out of the way. In the peak there are 16 thameslinks with 4 terminating at St Albans - terminating trains need extra time at the station.
 

edwin_m

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I would disagree. You should have a cross over north of St Albans once the St Albans terminators are out of the way. In the peak there are 16 thameslinks with 4 terminating at St Albans - terminating trains need extra time at the station.
That's not much different from what they have now with the crossovers just south of Harpenden. A stop at St Albans on the fasts eats up an extra path if the train before or after is non-stop.
 

mr_jrt

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As we're breaking out all the random ideas...how about extending the Hendon lines to south of St Albans (or however close you can get to it) and having Thameslink run fast from there (probably with a stop at West Hampstead though?) with a LO service on the freight lines taking up the slack (i.e. mirroring the WCML arrangements)...? Ignoring the feasibility or lack thereof, would that actually add sufficient capacity on the slow lines to cater for demand?
 

Bald Rick

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I would disagree. You should have a cross over north of St Albans once the St Albans terminators are out of the way. In the peak there are 16 thameslinks with 4 terminating at St Albans - terminating trains need extra time at the station.

Exactly. The terminators at St Albans occupy the down slow for a minimum of 4 minutes (planned, in reality a little longer) whilst they are cleared and then move down into the siding at little more than walking pace. There is then a 4 minute headway behind. This happens 4 times an hour, so the line is technically free for 28 minutes an hour, which has to accommodate the Luton semi-fasts (2 off peak, 4 peak), and freight (2 paths an hour, not all used). You can’t fit the fasts in as well, certainly not in the peak.

There are two further issues:

A) the down slow platform struggles to cope with the passenger numbers in the evening peak if a fast train stops there. 500-700 people can alight from each train, and it always takes at least 5 minutes to clear the platform, often 7 or 8. Not compatible with trains arriving 4 minutes apart.

B) Radlett and Harpenden junctions are generally operated as a pair, with DF-DS at Harpenden being a parallel move to US-UF at Radlett.
 

Bald Rick

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As we're breaking out all the random ideas...how about extending the Hendon lines to south of St Albans (or however close you can get to it) and having Thameslink run fast from there (probably with a stop at West Hampstead though?) with a LO service on the freight lines taking up the slack (i.e. mirroring the WCML arrangements)...? Ignoring the feasibility or lack thereof, would that actually add sufficient capacity on the slow lines to cater for demand?

Where would the “LO” service go to the south? Given that the TL core is full and St Pancras is full, and Belsize tunnels are 4 track.
 

38Cto15E

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Just out of interest I picked Radlett 0730-0830 weekdays.
Up slow 11 Thameslink trains, 8xstoppers, 3xnon stop. Up Fast 10 non stop 5xThameslink and 5xEast Midlands Trains.
A total of 21 Southbound trains in 60 minutes, there is very little margin if something goes wrong.
 
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