Cambridge South new station construction progress.

[Magdalia]

Btw when I was at school my English teacher taught me that saying "40 year old signalling panel" infers that the whole panel is 40 years old ! If you think it doesn't mean the whole thing isn't 40 years old you probably didn't get taught very well. Either way, you need to blame the teaching profession rather than the whine !! (As the statement is poor english whichever way you cut it).

I don't know when you were born, but when asked how old you are you almost certainly reply with the number of years since you were born. But various bits of you haven't been there all of your life, notably your teeth.

If we want to be pedantic the Cambridge signalling panel is more than 40 years old: it was first used in 1982 so is actually 42.

 

[yorkie]

Just a gentle reminder that this thread is to discuss updates regarding Cambridge South station.

We very much welcome the creation of new threads to discuss other topics, in the appropriate forum sections.

Thanks.

 

[Jimcam]

Photo today from the same point (Shepreth Branch Junction footbridge) as post 1155, showing the Royston lines now in their new position. Second photo looks north from the footbridge at the new Down WAML to Up Royston divergence (the junction is staggered), with the pointwork at a noticeably shallower angle than before. Lefthand track is the newly extended Down Royston, which merges into the Down WAML further north than before.

 

[Nicholas Lewis]

Photo today from the same point (Shepreth Branch Junction footbridge) as post 1155, showing the Royston lines now in their new position. Second photo looks north from the footbridge at the new Down WAML to Up Royston divergence (the junction is staggered), with the pointwork at a noticeably shallower angle than before. Lefthand track is the newly extended Down Royston, which merges into the Down WAML further north than before.

Is the better alignment off the Royston branch leading to an improvement to linespeed?

 

[Bald Rick]

Is the better alignment off the Royston branch leading to an improvement to linespeed?

slightly

 

[arb]

At the point where the King's Cross and Liverpool Street lines join, just south of the station, why does the northbound line from King's Cross now run alongside two main lines for such a long distance compared to before? Why doesn't the southbound line to King's Cross need to be distinct from the Liverpool Street lines for a similar distance? I assume that this has to be related to improving the junction speed, but how/why?

 

[takethegame]

I'm sure it's been covered before, but why not 4 track all the way from the junction to Cambridge South, to reduce conflicts and improve journey times, as all trains will be stopping at Cambridge South (?) and reduces the needs for changing tracks/conflicts/speed restrictions over points etc.

 

[Magdalia]

I'm sure it's been covered before, but why not 4 track all the way from the junction to Cambridge South, to reduce conflicts and improve journey times, as all trains will be stopping at Cambridge South (?) and reduces the needs for changing tracks/conflicts/speed restrictions over points etc.

It has been covered before. Four tracks all the way Shepreth Branch Junction-Cambridge was in the original Cambridge South proposals but subsequently removed. But it is proposed again for East West Rail.

 

[swt_passenger]

At the point where the King's Cross and Liverpool Street lines join, just south of the station, why does the northbound line from King's Cross now run alongside two main lines for such a long distance compared to before? Why doesn't the southbound line to King's Cross need to be distinct from the Liverpool Street lines for a similar distance? I assume that this has to be related to improving the junction speed, but how/why?

The southbound line towards Kings Cross includes a long high speed crossover onto the down line then another high speed turnout onto the up line towards Royston and Kings Cross. The down line coming from the Royston direction has to get right past all that, so the down direction junction points are somewhat further north than originally, and this is what you see as a third track.

In general, stretching the junction out like this increases the number of sets of points to four, but removes the need for a fixed diamond )or a switched diamond). Speed can be increased, and reliability and maintainability are increased.

 

[Steve Harris]

The southbound line towards Kings Cross includes a long high speed crossover onto the down line then another high speed turnout onto the up line towards Royston and Kings Cross. The down line coming from the Royston direction has to get right past all that, so the down direction junction points are somewhat further north than originally, and this is what you see as a third track.

In general, stretching the junction out like this increases the number of sets of points to four, but removes the need for a fixed diamond )or a switched diamond). Speed can be increased, and reliability and maintainability are increased.

In this case the number of sets of points hasn't actually increased, as the junction has had 4 sets of points for 35+ years (ever since Shepreth Branch Junction box was demolished and the junction remodeled).
But as you correctly (broadly) point out, it's now over a longer distance so the 'turnout' speeds can be increased. Yes the number of points has increased on the layout that was there in the 1970's (before we get a pedant alert).

This is the second time the junction has been remodeled in my lifetime and if EWR makes it to Cambridge I might be able to see a 3rd try at getting it right , that's a joke btw.

 

[Magdalia]

This is the second time the junction has been remodeled in my lifetime and if EWR makes it to Cambridge I might be able to see a 3rd try at getting it right

You get the pedantry anyway! This is now the third time.

Shepreth Branch Junction was remodelled twice in 1982/83 in order to make the transition from the manual signal boxes to the power box.

First time the new track layout and signalling replaced the old, but on the old alignment. After the Panel took over, and the old Shepreth Branch Junction box was demolished, the tracks were realigned, shifting the whole layout a bit to the east. The site of the old signal box has been under the up Liverpool Street line since then.

 

[Steve Harris]

You get the pedantry anyway! This is now the third time.

Shepreth Branch Junction was remodelled twice in 1982/83 in order to make the transition from the manual signal boxes to the power box.

First time the new track layout and signalling replaced the old, but on the old alignment. After the Panel took over, and the old Shepreth Branch Junction box was demolished, the tracks were realigned, shifting the whole layout a bit to the east. The site of the old signal box has been under the up Liverpool Street line since then.

How come you replying doesn't surprise me !
Note: I did say remodeled rather than changed like for like so by your own admission ("First time the new track layout and signalling replaced the old, but on the old alignment") that count is still actually 2. As an example changing a filling (which has failed) in a tooth is not remodeling, But taking the tooth out and inserting an implant in is (As I know you like the dentistry analogies ).

 

[Magdalia]

How come you replying doesn't surprise me !
Note: I did say remodeled rather than changed like for like so by your own admission ("First time the new track layout and signalling replaced the old, but on the old alignment") that count is still actually 2. As an example changing a filling (which has failed) in a tooth is not remodeling, But taking the tooth out and inserting an implant in is (As I know you like the dentistry analogies ).

Neither of the changes in 1982/83 were "like for like", both were remodelling. The first change was when the junction points were altered from double lead to single lead. Obviously that required other small changes so that everything joined up. The second change was like what is happening now, with the points moved and tracks realigned. The key point (!) is that both times the junction had changed and trains passing through the junction had a changed route.

A similar example is through the new station itself, where the old plain track ended a year ago, we have had the tracks through platforms 3 and 4 for a year, and we will get new track again on 6 January.

(And no I'm not a fan of dentistry, or dentistry analogies, though your analogy would have worked better if you had compared implants with braces!)

 

[Maltazer]

What's wrong with wine ? Afterall it is Christmas and some people like a drink at this time of year.

Btw when I was at school my English teacher taught me that saying "40 year old signalling panel" infers that the whole panel is 40 years old ! If you think it doesn't mean the whole thing isn't 40 years old you probably didn't get taught very well. Either way, you need to blame the teaching profession rather than the whine !! (As the statement is poor english whichever way you cut it).

I’ll bet you play golf

 

[StewartB]

Good coordination would mean the guided bus way busses drop at Cambridge North for a metro type shuttle into Cambridge and Cambridge south

Virtually impossible to achieve. While the busway itself benefits from speed, exact timings are very hard to achieve as buses from Huntingdon/St. Ives still have to fight normal road traffic to get onto it and once there dwell times are extremely variable depending on loadings.

It would be very easy to achieve with a dedicated St Ives-Cambridge North shuttle where the buses did not leave the busway.

You would have thought so, but in my repeated experience, even when the guided buses are already on the busway and reported as on time several stops to the west of Cambridge, by the time they arrive at Cambridge Science Park, which is the final busway stop before Cambridge North, they are almost always late, often by 5-10 minutes. Almost every time I choose to rely on it, I end up regretting it, as I have missed so many trains due to the unreliability of the guided bus - and that's the section you'd have thought would be most reliable because it is on the busway!

I would use a shuttle between Cambridge and Cambridge North - I do that trip from time to time (£1.75 single/£1.80 return at the weekend with a Network Card) - cheaper than the bus - but the long gaps in the current timetable mean I have to plan journeys rather than just turn up and go, so a frequent shuttle service would be lovely for me.

 

[St. Paddy]

Is the better alignment off the Royston branch leading to an improvement to linespeed?

50mph on the up, remains at 30mph on the down

 

[Steve Harris]

I’ll bet you play golf

Nah, snooker !!

 

[Jimcam]

50mph on the up, remains at 30mph on the down

Are you sure about that? Trains from the Down Royston line only have to negotiate one set of trailing points, where that line merges with the Down WAML. It seems perverse if Up Royston trains, which follow a more complicated path, with two facing and one trailing sets of points, are able to do that 20 mph faster than their northbound cousins...What is the constraint that will limit the Down trains to 30?

 

[sharpener]

It has been covered before. Four tracks all the way Shepreth Branch Junction-Cambridge was in the original Cambridge South proposals but subsequently removed. But it is proposed again for East West Rail.

Because then EWR will have to bear the cost? Seems a missed opportunity to tidy it all up though.

The southbound line towards Kings Cross includes a long high speed crossover onto the down line then another high speed turnout onto the up line towards Royston and Kings Cross. The down line coming from the Royston direction has to get right past all that, so the down direction junction points are somewhat further north than originally, and this is what you see as a third track.

In general, stretching the junction out like this increases the number of sets of points to four, but removes the need for a fixed diamond )or a switched diamond). Speed can be increased, and reliability and maintainability are increased.

A diamond gives a much smoother ride though bc there is not the intermediate bit of straight track which makes the centripetal force start and stop twice.

50mph on the up, remains at 30mph on the down

Surprising it is not more on the down where there are fewer sets of points. Perhaps it doesn't matter as (nearly) all trains are scheduled to stop at C. South so will be decelerating anyway.

 

[neill]

Are you sure about that? Trains from the Down Royston line only have to negotiate one set of trailing points, where that line merges with the Down WAML. It seems perverse if Up Royston trains, which follow a more complicated path, with two facing and one trailing sets of points, are able to do that 20 mph faster than their northbound cousins...What is the constraint that will limit the Down trains to 30?

Could be the tighter radius on the curve after the junction?

 

[uglymonkey]

Can it be a branch line ( techically) if its connected at both ends ??

 

[gm671]

Surprising it is not more on the down where there are fewer sets of points. Perhaps it doesn't matter as (nearly) all trains are scheduled to stop at C. South so will be decelerating anyway.

Due to be increased at a later stage of the works. Definitely not braking for the station back there... easily back up to 50/60mph after the junction in a 387 or 700.

 

[sharpener]

Can it be a bransch line ( techically) if its connected at both ends ??gob

Was constructed as two branch lines joined end-on. To begin with there was a change of locomotive at Shepreth.

Complicated history, original plan was to connect with a Cambridge - Bedford route at Shepreth Good summary here.

 

[WeGoAgain]

50mph on the up, remains at 30mph on the down

Correct.

 

[St. Paddy]

Are you sure about that? Trains from the Down Royston line only have to negotiate one set of trailing points, where that line merges with the Down WAML. It seems perverse if Up Royston trains, which follow a more complicated path, with two facing and one trailing sets of points, are able to do that 20 mph faster than their northbound cousins...What is the constraint that will limit the Down trains to 30?

I’m fairly confident about this as it’s in the Driver briefing I received and also the weekly notices from Network Rail. Apparently, it was planned to be 40mph on the down at the design stage but has been reduced due to signal sighting issues.

 

[Nicholas Lewis]

I’m fairly confident about this as it’s in the Driver briefing I received and also the weekly notices from Network Rail. Apparently, it was planned to be 40mph on the down at the design stage but has been reduced due to signal sighting issues.

Is that short term due to current position of signals or the final solution?

The Down would have needed realigning to get better geometry for the Up move which presumably is more beneficial for improving Jcn clearance times.

 

[MikePJ]

Was constructed as two branch lines joined end-on. To begin with there was a change of locomotive at Shepreth.

Complicated history, original plan was to connect with a Cambridge - Bedford route at Shepreth Good summary here.

The line was built by the Eastern Counties Railway, who seemed to pursue a strategy of constructing on the cheap in order to expand as widely as possible. This is evident on several lines but especially between Cambridge and Shepreth, where not only do we have the sharp bend at the junction but also the execrable Foxton Crossing, which was built on a skew across a road junction in a way that must have been unwise even then! Anyway, back in 2017 I got the drawings for the 1847 proposal for the line to Bedford from the County Archives and photographed them - you can see them here. This line was eventually built between Cambridge and Shepreth only.

Here's the drawing for what became Shepreth Branch Junction. I can't find the higher-resolution version of this at the moment (sorry) but I think the curvature is specified at "5 furlongs 8 chains" (equivalent to 1167m).

 

[St. Paddy]

Is that short term due to current position of signals or the final solution?

The Down would have needed realigning to get better geometry for the Up move which presumably is more beneficial for improving Jcn clearance times.

Not sure if there’s any future options.

 

[Magdalia]

Is that short term due to current position of signals or the final solution?

The Down would have needed realigning to get better geometry for the Up move which presumably is more beneficial for improving Jcn clearance times.

I have been to have a look, and I am mystified, because both of the relevant signals have been moved.

On the down road coming from Shepreth CA123 is the last signal before the junction. Until Christmas Eve it was positioned on the curve and can be seen next to the 13th wagon on the right edge of this picture, which is taken from the blue footbridge that crosses the track at the old junction:

6M04 1157 Barrington Sidings, Foxton - Willesden 09-06-23

66734 passing Shepreth Branch Junction

www.flickr.com

6M04 1157 Barrington Sidings, Foxton - Willesden 09-06-23

The 30mph board is partially obscured in the picture and is next to the 6th wagon. CA123 also had a banner repeater which was before the start of the curve, Shepreth side of the Shelford Road bridge.

The new CA123 is north of the old junction and the blue footbridge, roughly opposite the old CA140 signal* on the up road that had the feathers for the branch. It still has a banner repeater which has also been moved, now it is just before the blue bridge, roughly where the GN MP55¼ is next to the 4th wagon in the picture.

The first signal after the junction is CA141 and this has also been moved. Previously it was just after Dukes No 2 crossing, there is already no trace of the exact location, but the new CA141 signal is much further north, near to GE MP53¾ and the bridge over the Nine Wells stream. To give some idea of distance GE MP53 was next to the Websters crossing which is in the bottom left hand corner of the picture, so the new CA141 is a three-quarter mile north of the old junction.

Given that the track geometry is set up for 40 mph, and both signals have been moved, what has gone wrong so that the new signals have been placed in locations where sightlines are inadequate for 40 mph running?

*not directly relevant, but CA140 is also being moved further north, the new CA140 will be roughly in line with White Hill farm nearer to the Nine Wells stream than the old junction.

 

[dk1]

50mph on the up, remains at 30mph on the down

Yes I noticed that on the yellow peril.