Why Are Some Straight Lines So Slow?

[sw1ller]

Sitting in the front of a 197 along the route I’m glad it’s only 75! Any faster and I’d be out my seat! Before any line speed improvements are made, the route would benefit much more from more signal sections between Runcorn east and Chester. The route is getting quite busy and when the liverpools are back to full strength you can get held for quite some time waiting for the sections to clear.

As lovely as Helsby station and box is, it needs modernising to allow for more trains. But the same could be said about anywhere north of Southampton to be fair!

 

[zwk500]

Bit surprised the politicians didn't get involved - "why is Wales' main line slower than everybody elses"

Because politicians (with a couple of exceptions) haven't got a clue about such details and nor do they give a fig - they'd have been told Wales was getting Shiny new trains and x minutes knocked off the journey time, which is what they care about.

I used to be involved in NR upgrades and improvements projects, and every conversation with politicians was always about the Journey times. Linespeed was only mentioned as a means to achieving said ends (e.g. <Place> in 90 minutes from London), and only then by certain people who looked closer at rail.

 

[The Planner]

Bit surprised the politicians didn't get involved - "why is Wales' main line slower than everybody elses"

Doubt they either knew about it or weren't interested. Its pretty rare you get political intervention unless its making them look good.

 

[Meerkat]

Doubt they either knew about it or weren't interested. Its pretty rare you get political intervention unless its making them look good.

I was thinking on the lines of some clickbait in the media being picked up by those with an agenda to show being hard done by

 

[The Planner]

I was thinking on the lines of some clickbait in the media being picked up by those with an agenda to show being hard done by

Even then its forgotten about relatively quickly, or they are told its going to cost x so y can't be done instead.

 

[zwk500]

I was thinking on the lines of some clickbait in the media being picked up by those with an agenda to show being hard done by

Nobody really cares about linespeed though outside of enthusiasts. Journey time is king and that is what will generate clicks.

 

[Annetts key]

Bit surprised the politicians didn't get involved - "why is Wales' main line slower than everybody elses"

Has no one told you? The Western does not have slow lines…

 

[Envoy]

Exactly this, when Newport and the area was resignalled, it was looked at but wasn't considered value for money.

Am I right in thinking that penny pinching Network Rail re-signalled the south Wales main line from STJ to Cardiff but did not think that the line would be electrified so the gantries were too low for catenary. Then the whole lot had to be ripped up and the new gantries installed at a height that allowed for electrification? How many years did the signalling last until having to be replaced again - assuming I am right?

 

[The Planner]

Am I right in thinking that penny pinching Network Rail re-signalled the south Wales main line from STJ to Cardiff but did not think that the line would be electrified so the gantries were too low for catenary. Then the whole lot had to be ripped up and the new gantries installed at a height that allowed for electrification? How many years did the signalling last until having to be replaced again - assuming I am right?

No idea. Though if at the time of development it was decided it wasnt a prospect then it happens. To be a pedant, the signalling hasnt been replaced, the gantries have if thats the case.

 

[zwk500]

Am I right in thinking that penny pinching Network Rail re-signalled the south Wales main line from STJ to Cardiff but did not think that the line would be electrified so the gantries were too low for catenary. Then the whole lot had to be ripped up and the new gantries installed at a height that allowed for electrification? How many years did the signalling last until having to be replaced again - assuming I am right?

https://www.railengineer.co.uk/cardiff-area-signalling-renewal/ this article suggests the CASR (Cardiff Area Signalling Renewal) was done to electrification-ready standards in 2016, and that was the first renewal since the 60s.

 

[The Planner]

https://www.railengineer.co.uk/cardiff-area-signalling-renewal/ this article suggests the CASR (Cardiff Area Signalling Renewal) was done to electrification-ready standards in 2016, and that was the first renewal since the 60s.

NASR (Newport) was 2010.

 

[Annetts key]

I don’t know about on the Wales side, but on the English side, the signal structures were supposed to be compliant with OHL. They were a mix of new signal structures and existing structures with new heads and fittings and fixtures.

However, when the OHL was actually installed, although the clearance to the OHL live wires was okay, there was a problem in that staff were banned from climbing them while the line was open to traffic, as there was insufficient clearance distance from the pantograph on a passing train and a member of staff. It was explained that at the time the signalling was designed, the final specifications for the OHL were not available.

The result was that the signal structures concerned were either modified or completely replaced.

 

[Parham Wood]

I don’t know about on the Wales side, but on the English side, the signal structures were supposed to be compliant with OHL. They were a mix of new signal structures and existing structures with new heads and fittings and fixtures.

However, when the OHL was actually installed, although the clearance to the OHL live wires was okay, there was a problem in that staff were banned from climbing them while the line was open to traffic, as there was insufficient clearance distance from the pantograph on a passing train and a member of staff. It was explained that at the time the signalling was designed, the final specifications for the OHL were not available.

The result was that the signal structures concerned were either modified or completely replaced.

I am trying to get my head around this comment or rather why it was not possible to design the signal structures for OHL. The traction wire goes down the middle of the track more or less (I guess it wiggles a bit to even out pantograph wear), we have fairly standard pantographs so the height of the traction wire is known. You are not going to place signals next to the OHL gantries. So in theory the pantograph footprint is known more or less. So how come the signalling could not be designed for OHL? OK I am probably missing something but to a layman it seems a feable excuse. Yes I know signal sighting etc may require signals to be moved when OHL is installed so not all would be compliant in any event.

 

[Bertie the bus]

I was thinking on the lines of some clickbait in the media being picked up by those with an agenda to show being hard done by

Just to put it into some sort of perspective. If a train travelled at 95 mph all the way from Cardiff to Newport it would take 7 1/2 minutes. If it travelled at 125 mph all the way it would take 5 3/4 minutes. Obviously no trains do that as they stop at both so the difference in time by raising the speed limit would probably be close to 1 minute. I can't imagine even the most desperate politician making a huge fuss over getting from Newport to Cardiff 1 minute quicker.

 

[zwk500]

NASR (Newport) was 2010.

Was it electrification-ready?

 

[najaB]

I can't imagine even the most desperate politician making a huge fuss over getting from Newport to Cardiff 1 minute quicker.

And surely the longer it takes to get Newport, the better.

(Sorry, couldn't resist.)

 

[The Planner]

Was it electrification-ready?

No idea, will see if Ive got anything I can dig out.

 

[hooverboy]

Could also be to do with the strength of underline structures and clearances on the dynamic profiles.

Indeed.There are several bits of very straight track on the anglia branches,however some of it is crossing some very soft ground with a lot of give underneath.Needless to say the speed and type of stock allowed is restricted.
Case in point would be the incident with one of the GA flirts recently,you can quite clearly see how the earthworks are very much subject to the elements.

 

[snowball]

A search finds a few previous references, such as post #3784 in the original GW electrification thread.

 

[Annetts key]

I am trying to get my head around this comment or rather why it was not possible to design the signal structures for OHL. The traction wire goes down the middle of the track more or less (I guess it wiggles a bit to even out pantograph wear), we have fairly standard pantographs so the height of the traction wire is known. You are not going to place signals next to the OHL gantries. So in theory the pantograph footprint is known more or less. So how come the signalling could not be designed for OHL? OK I am probably missing something but to a layman it seems a feable excuse. Yes I know signal sighting etc may require signals to be moved when OHL is installed so not all would be compliant in any event.

I don’t believe the issue was the height, but rather the horizontal distance between the nearest point that any part of the pantograph on a train came to the signal structure and a person working on said structure.

Don’t worry, the railway employees were just as confused as you are at why this happened.

 

[Gathursty]

Nobody really cares about linespeed though outside of enthusiasts. Journey time is king and that is what will generate clicks.

Given many drivers whinge about speed limits/speed cameras, I'd be reluctant to agree with your point.

 

[zwk500]

Given many drivers whinge about speed limits/speed cameras, I'd be reluctant to agree with your point.

Car drivers moan about speed limits and cameras because they constrain their ability to act like idiots. Which is markedly different from Rail Journey planning and politics.

 

[Annetts key]

Car drivers moan about speed limits and cameras because they constrain their ability to act like idiots. Which is markedly different from Rail Journey planning and politics.

That made me chuckle

 

[nw1]

For context, the GWML west of Bristol and Westbury does not exceed 100mph (except for some very brief sections around Highbridge), and the Crosscountry route between Birmingham and Bristol/Cardiff also doesn't exceed 100mph.

That route actually always seems very quick to me and it seems amazing how much distance you cover in a short time. But that's probably because I'm comparing it with the much slower XC route from Reading to Birmingham.

Certainly if the route via Reading is disrupted due to engineering work, with a good connection it isn't a whole lot slower to travel from Hampshire to Birmingham via Bristol, or at least that was the case in the early 10s when I last did it.

 

[robert thomas]

And surely the longer it takes to get Newport, the better.

(Sorry, couldn't resist.)

Conversly the quicker it takes to get out ofNewport......