Cambridge Area Signalling Renewal

[Alarmkid23]

No of course not. They do it just in time for trains to get the distant so down the least amount of time possible. Did you mean Harling Road?

yes

 

[yorkie]

Reopened.fo enable @snowball to post an update

 

[snowball]

Reopened.fo enable @snowball to post an update

You must have the wrong name there. I don't have any news to post.

 

[Snow1964]

You must have the wrong name there. I don't have any news to post.

It was me, as Transport Works Act decision has been published. 2 level crossing upgrades rejected, others agreed

The order grants powers to Network Rail to enable the construction and operation of a scheme of re-signalling of the railway in the Cambridge area and to upgrade the level crossings at Croxton, Dullingham, Dimmock’s Cote, Milton Fen and Six Mile Bottom also within the Cambridge area. Consent to upgrade 2 further level crossings at Meldreth Road and Waterbeach has been refused

Cambridge re-signalling: Transport and Works Act order

Approval for Network Rail to renew the signalling system for the Cambridge area.

www.gov.uk

 

[Class 170101]

Do we know why two were rejected?

 

[swt_passenger]

Do we know why two were rejected?

It’s most of a page towards the end of the TWA inspectors report, starts at para 4.91 (Meldreth), and at 4.93 (Waterbeach). The inspector seems to have agreed that changes to the existing crossings were not going to improve matters enough to justify the increased closure periods, but I’d recommend reading it, I might have got it wrong…

 

[Brissle Girl]

Do we know why two were rejected?

The link in the post above yours includes both the Inspector’s report and the SoS’s decision letter, so probably best that you read them if you are interested in the detail.

 

[snowball]

The hazards of proposing something near Cambridge - objectors at Meldreth were represented by a local resident, vice-chair of the parish council, who is a professor with expertise in operational research including stochastic modelling, so he was able to critically review NR's evidence on the modelling of delays. (Inspector's Report 2.18ff)

At Waterbeach, delays to station users were a factor.

 

[Freightmaster]

The hazards of proposing something near Cambridge - objectors at Meldreth were represented by a local resident, vice-chair of the parish council, who is a professor with expertise in operational research including stochastic modelling,

Just when I thought I had heard everything when it comes to NIMBYism,
now we have "level crossings and chaos theory" to add to the list!

I wonder how long it will be before we hear about "Schrödinger's AHB barriers"
which pose are a serious safety issue because they cannot be proven to be up
or down unless someone observes them as such...



MARK

 

[dk1]

Just when I thought I had heard everything when it comes to NIMBYism,
now we have "level crossings and chaos theory" to add to the list!

I wonder how long it will be before we hear about "Schrödinger's AHB barriers"
which pose are a serious safety issue because they cannot be proven to be up
or down unless someone observes them as such...



MARK

I just don’t understand how anybody can be so bothered to pursue such things.

 

[Belperpete]

The hazards of proposing something near Cambridge - objectors at Meldreth were represented by a local resident, vice-chair of the parish council, who is a professor with expertise in operational research including stochastic modelling, so he was able to critically review NR's evidence on the modelling of delays. (Inspector's Report 2.18ff)

At Waterbeach, delays to station users were a factor.

Except the inspector seems to have given fairly short shrift to the professor's and others' objections about the methodology used by Network Rail for the modelling. I suspect that the professor's evidence may have been tainted by him claiming to represent the parish council without any evidence of authority to do so, and by him then launching into conspiracy theories!

In most cases, local residents are usually quite keen to get "unsafe" half-barrier crossings replaced by safer full-barrier crossings. However, in this case, the local residents had already first-hand experience of the impact that such a conversion can have on road traffic, and so there were a lot of objections to further such conversions. I was impressed by how methodically the inspector considered each individual crossing, and was prepared to go against ORR guidance in reaching his decisions.

 

[dk1]

Waterbeach level crossing is awful and potentially dangerous. As train drivers passing through we dread another train being stopped in the station.

Was looking forward to conversion to CCTV or MCBOD.

 

[Magdalia]

I was impressed by how methodically the inspector considered each individual crossing, and was prepared to go against ORR guidance in reaching his decisions.

I have read the report. One thing it does demonstrate is that the Transport and Works Act Order inquiry process is not just a "rubber stamp" giving Network Rail everything that they want.

objectors at Meldreth were represented by a local resident, vice-chair of the parish council, who is a professor with expertise in operational research including stochastic modelling, so he was able to critically review NR's evidence on the modelling of delays. (Inspector's Report 2.18ff)

Except the inspector seems to have given fairly short shrift to the professor's and others' objections about the methodology used by Network Rail for the modelling.

I have studied operational research and stochastic modelling, though it was a long time ago. I agree with the professor and not Network Rail, and it is not clear what independent advice the inspector took on the methodology, if any. In particular, the professor is correct that Network Rail's methodology is deficient in that it does not take proper account of the train timetable not being random (para 2.21). One of the biggest pitfalls, when using many statistical methodologies, is failing to recognise when the methodology breaks down because randomness assumptions are inappropriate.

This is well illustrated by Meldreth Road. Here are the booked passing times of trains at Shepreth (only 30 chains distant from Meldreth Road) in a typical hour:

xx00
xx02
xx20
xx23
xx30
xx32
xx38
xx39
xx49
xx53

Just looking at that pattern, it is obvious that CCTV monitored barriers will be going down for 2 trains more often than they will be going down for 1 train. I remain unconvinced that Network Rail's methodology takes proper account of this.

In particular, Network Rail's response at paragraphs 3.66-3.70 demonstrates that they don't understand this issue. The last sentence of paragraph 3.67 shows a worrying disregard by Network Rail of any independent review or criticism of their methodology.

experts, who spend their professional lives dealing with these issues (ie the Modelling Group and the Highways Authority), consider the methodology used and the results obtained to be robust.

They think they know more about the methodology than a professor with a "professional background and qualifications in the field of Operations Research include a background in the modelling of stochastic process" (para 2.18).

I suspect that the professor's evidence may have been tainted by him claiming to represent the parish council without any evidence of authority to do so

The evidence is there: it is in the Inspector note at the end of paragraph 3.66.

Inspector Note: Prior to the Inquiry Mr James advised me, via the Programme Officer, that he had been asked to speak at the Inquiry on behalf of Meldreth Parish Council and his Statement of Case, thus reflect this. Moreover, INQ-28 makes clear Meldreth Planning Committee, a committee of the Parish Council, objected to the planning application for the level crossing upgrade at Meldreth Road citing similar concerns to those set out in the Statement of Case. Parties who have not submitted a written objection to the Order can, at my discretion, be heard at the Inquiry.

 

[OxtedL]

Waterbeach level crossing is awful and potentially dangerous. As train drivers passing through we dread another train being stopped in the station.

Was looking forward to conversion to CCTV or MCBOD.

Yes I find it really hairy as an occasional passenger. Surprised this one isn't being fixed.

 

[Snow1964]

Yes I find it really hairy as an occasional passenger. Surprised this one isn't being fixed.

Reading the report, it seems the Inspector was led to believe that Waterbeach station was being relocated during 2025, so proximity of station was a factor that would no longer be relevant

 

[dk1]

Reading the report, it seems the Inspector was led to believe that Waterbeach station was being relocated during 2025, so proximity of station was a factor that would no longer be relevant

I was under the impression that had all been put on hold.

 

[Snow1964]

I was under the impression that had all been put on hold.

The application was in 2022, Inspectors report dated October 2023 (although only just published).

Presumably Inspector received info around first half of 2023, and things might have changed afterwards.

I guess that is why some countries don't allow variations to capital commitments within 3-6 years depending on country, to avoid plans changing and conflicting.

 

[Class 170101]

It’s most of a page towards the end of the TWA inspectors report, starts at para 4.91 (Meldreth), and at 4.93 (Waterbeach). The inspector seems to have agreed that changes to the existing crossings were not going to improve matters enough to justify the increased closure periods, but I’d recommend reading it, I might have got it wrong…

The link in the post above yours includes both the Inspector’s report and the SoS’s decision letter, so probably best that you read them if you are interested in the detail.

Sorry, I thought the link only included the Order itself not a report to go with it.

I have studied operational research and stochastic modelling, though it was a long time ago. I agree with the professor and not Network Rail, and it is not clear what independent advice the inspector took on the methodology, if any. In particular, the professor is correct that Network Rail's methodology is deficient in that it does not take proper account of the train timetable not being random (para 2.21). One of the biggest pitfalls, when using many statistical methodologies, is failing to recognise when the methodology breaks down because randomness assumptions are inappropriate.

This is well illustrated by Meldreth Road. Here are the booked passing times of trains at Shepreth (only 30 chains distant from Meldreth Road) in a typical hour:

xx00
xx02
xx20
xx23
xx30
xx32
xx38
xx39
xx49
xx53

Just looking at that pattern, it is obvious that CCTV monitored barriers will be going down for 2 trains more often than they will be going down for 1 train. I remain unconvinced that Network Rail's methodology takes proper account of this.

Surely it is better for barrier downtime to have two trains passing at once rather than those trains being spread around the hour? If they were spread surely rhe barrier downtime is even longer?

 

[PG]

Surely it is better for barrier downtime to have two trains passing at once rather than those trains being spread around the hour? If they were spread surely rhe barrier downtime is even longer?

As @dk1 has posted above (Post #102) the thing with Waterbeach is people, especially pedestrians and cyclists, assuming that they can cross as soon as a train has stopped at the platform, not thinking of a through train coming in the opposite direction.

 

[Class 170101]

As @dk1 has posted above (Post #102) the thing with Waterbeach is people, especially pedestrians and cyclists, assuming that they can cross as soon as a train has stopped at the platform, not thinking of a through train coming in the opposite direction.

Thats indeed a risk similar to what happened at Elsenham. However what I was referring to was MCB CCTV / MCB OD Crossings where the overall downtime must be shorter if two trains pass each other versus spreading all the trains acroiss the hour.

 

[MarkyT]

Thats indeed a risk similar to what happened at Elsenham. However what I was referring to was MCB CCTV / MCB OD Crossings where the overall downtime must be shorter if two trains pass each other versus spreading all the trains acroiss the hour.

People stepping out behind a train that has just passed is a common hazard around the world, especially in many overseas stations where passengers have crossed the track historically on the level routinely, which is why many nations have been busy eliminating such foot crossings widely when modernising stations. Clearly, Full Barrier solutions protect against that far better than Half Barriers, where a public road is involved. The problem is that an MCB, the default UK FB solution, whether equipped with OD or not, almost invariably and dramatically increases the road closure time for each train. To minimise road closure time it's always good to try and arrange for opposing direction trains to pass at the crossing if possible, but with multiple sites along a line that becomes increasingly difficult, though a planner might concentrate on implementing it at the most important or busiest crossing. A problem where the timetable is so arranged is that a 5 minute delay in realtime running in one direction probably doesn't give enough time for the barriers to rise after the 1st train passes on time, for the road traffic to clear, and for a full road warning sequence to be given again in time to avoid a cautionary aspect being seen by the late running 2nd train, so the crossing often remains closed for that extra 5 minutes. Then (say), an early running freight turns up behind the 1st train, a heavy consist the signaller really doesn't want to have to stop before the big gradient just ahead (not in East Anglia clearly!)... Those few-minutes magnitude delays are fairly common and may be caught up later in some pathing time through a major hub or at the next diagrammed turnround, so aren't in themselves too concerning from a network-wide perspective, but a planned 3 minute closure of a crossing en-route can easily turn into 8 minutes or more very quickly. Stations affect MCB closure times, where close to a crossing. Depending on layout, sometimes closure can be delayed until shortly before a departure, with the protecting signal held at red during run-in. Typically, this applies in one direction only although staggered platforms could plausibly allow it in both. There's more chance of any overrun hitting road users in this arrangement however, which is why signallers are instructed to lower the barriers early at many busy crossings, even if the particular site's interlocking doesn't enforce that.

 

[Bald Rick]

it will be interesting to see what ORR do here.

The definition of ‘Reasonably Practicable’ has been tested and effectively changed.

 

[MikeWM]

I think the Waterbeach decision is very sensible, at least as things stand right now. As I pointed out earlier in this thread (last year), if the barriers were 'upgraded' then under the current Sunday timetable you would have to get to the station 15-20 minutes early if arriving 'from the wrong side' of the station in order to guarantee catching your train (or risk missing it and having to wait an hour for the next one). That's clearly unacceptable for passengers. (And even though the road is fairly lightly used, that amount of continuous downtime doesn't seem acceptable for road users either).

I personally still see no need to upgrade Milton Fen either - it is lightly used and there are no issues with sighting, the track is straight - but looks like that one will be going ahead. It's a while since I've walked that way so it won't be a massive inconvenience to me, at least.

 

[Class 170101]

I personally still see no need to upgrade Milton Fen either - it is lightly used and there are no issues with sighting, the track is straight - but looks like that one will be going ahead. It's a while since I've walked that way so it won't be a massive inconvenience to me, at least.

Is that not the one where there is a Gypsy encampment?

 

[MikeWM]

Is that not the one where there is a Gypsy encampment?

No, it's the one the other side of the A14, between Milton Village and the Cam (just north of Baits Bite lock). All it gets is a rare vehicle going to park by the river, and the occasional pedestrian/cyclist.

You're probably thinking of Chesterton Junction, just to the south of Cambridge North - but that one is already full barrier.

 

[Steve Harris]

No, it's the one the other side of the A14, between Milton Village and the Cam (just north of Baits Bite lock). All it gets is a rare vehicle going to park by the river, and the occasional pedestrian/cyclist.

You're probably thinking of Chesterton Junction, just to the south of Cambridge North - but that one is already full barrier.

I think the confusion stems from both crossings being on roads named 'Fen Road', as you rightly say, one is just outside Milton and the other is in Cambridge.

The former can be used as a route to Milton Country Park from the River Cam (/Granta) and it is a nice bicycle ride from Cambridge to boot (far better than using Milton Road).

 

[jammmmmsssssss]

Wouldn't making croxton a MCB solve the really long signal block at Thetford. I often see ga's to Norwich get delayed a lot here by late running emr's

 

[dk1]

Wouldn't making croxton a MCB solve the really long signal block at Thetford. I often see ga's to Norwich get delayed a lot here by late running emr's

I think that is the plan. Croxton is being converted to MCB-OD and the new signal bases are already in place. Just got to hope this is a new signal section particularly in the down direction.

 

[jammmmmsssssss]

I think that is the plan. Croxton is being converted to MCB-OD and the new signal bases are already in place. Just got to hope this is a new signal section particularly in the down direction.

That's good

It's similar to the one between elmswell and Thurston towards Cambridge (don't know if it's up or down) where trains to Cambridge get delayed behind late running freights

Also, when will the project get completed. I haven't heard much about it in a while

 

[dk1]

That's good

It's similar to the one between elmswell and Thurston towards Cambridge (don't know if it's up or down) where trains to Cambridge get delayed behind late running freights

The problem started when Croxton had the 40TSR imposed around 15 years ago then was made worse in 2012 with resignalling of the Breckland line. Signal sections where basically just a like for like replacement but no signal replaced the down IBH just east of Thetford station meaning trains cannot enter Thetford station until the preceding service has cleared Harling Road.

Also, when will the project get completed. I haven't heard much about it in a while

No idea. These things tend to slip.