Which routes in the UK make sense to increase linespeeds to 200 km/h (125 mph)

[The Planner]

I'm still trying to understand the implications of mixing different speeds on one line. Can anyone please tell me what is the difference in running times from Preston to Glasgow for the following?

1. a 125mph EMU with tilt, e.g. Pendolino
2. a 125mph EMU without tilt, e.g. 80x
3. a 110mph non-tilting train like class 350

The whole reason Project 110 for LM was to get them fast line paths on the WCML. 100mph didnt work.

 

[zwk500]

What about acceleration? Maybe the slower train gets to 110 before the faster one, so some of the 125 capability is used up catching the slower train. And getting from 110 to 125 can take a while.

Acceleration does indeed make a difference. But it's difficult to make a generalised abstraction about it, other than 'allow about 90-120 seconds'.

 

[alf]

This afternoon I travelled from Uckfield to London Bridge on the hourly DMU.
It runs ‘non stop’ from Oxted to East Croydon missing the 4 station stops served by East Grinstead trains.

It runs down hill from the tunnel just north of Oxted reaching 85 mph.
Then it sits outside South Croydon at the Brighton line Junction for a timetabled four minutes.
This happens on every up Uckfield train for the last three years.

There is no point in raising a line speed to say 125 mph if Network Rail then timetable recovery time equivalent to a line speed of say 80 mph, or in the Uckfield case equivalent to an average speed of 41 mph.
It is annoying for passengers, wasteful for the environment, for fuel/ electric use & train/track wear & tear.

With Network Rail’s Uckfield Line mentality there is no point in line speed increases.
With the late Gerry Fiennes & the late Adrian Shooter & his colleagues’ mindset there is every point!

 

[Bald Rick]

With Network Rail’s Uckfield Line mentality

Why is it Network Rail’s ‘mentality’ ?

 

[zwk500]

There is no point in raising a line speed to say 125 mph if Network Rail then timetable recovery time equivalent to a line speed of say 80 mph, or in the Uckfield case equivalent to an average speed of 41 mph.

Of course, the Oxted line does not have a 125mph line speed.

 

[The Planner]

This afternoon I travelled from Uckfield to London Bridge on the hourly DMU.
It runs ‘non stop’ from Oxted to East Croydon missing the 4 station stops served by East Grinstead trains.

It runs down hill from the tunnel just north of Oxted reaching 85 mph.
Then it sits outside South Croydon at the Brighton line Junction for a timetabled four minutes.
This happens on every up Uckfield train for the last three years.

There is no point in raising a line speed to say 125 mph if Network Rail then timetable recovery time equivalent to a line speed of say 80 mph, or in the Uckfield case equivalent to an average speed of 41 mph.
It is annoying for passengers, wasteful for the environment, for fuel/ electric use & train/track wear & tear.

With Network Rail’s Uckfield Line mentality there is no point in line speed increases.
With the late Gerry Fiennes & the late Adrian Shooter & his colleagues’ mindset there is every point!

Which clearly shows why a lot of schemes can be proposed but as they cannot be timetabled to benefit from them they don't happen. Which is the correct thing to do. You don't spend the cash if you can't get anything from it.

 

[brad465]

Exeter to Reading already permits 110 on a number of sections.

Similar Cogload Jcn (where the Berks & Hants line from Reading to Exeter joins the Bristol to Exeter Line) to Bristol has an 8.5 mile section of 110mph.

Finally, Bristol to Birmingham is 100 for long distances, much of it 90/HST 100 so already I suspect signal spacing would be an issue.

There were intentions as part of the upgrades for Operation Princess thar weren't carried out (some were, such as Birmingham to Derby) to upgrade Birmingham to Taunton to 120mph and Birmingham to Oxford to 115mph.

I suspect the usual cost/benefit ratio found it was of modest benefit to journey times for the costs involved.

BR planned to upgrade Cogload to Exeter via Taunton to 125 by 1985 to improve the journey times of the NE-SW HST services, but with cuts to those in both 1984 and 1985 it never saw fruition and the 100mph limit (already an increase over the steam era 90) has perpetuated ever since.

I do wonder how much time you would save by making as much of Bristol to Exeter 125mph. Would it even be 8 mins, let alone 10 or more?

While not in any way a valid test, I have used Train Simulator to drive Bristol to Exeter and done it at 125mph where it's relatively smooth/straight. I only managed to save about 5 minutes from Bristol to Taunton compared to a 30 minute journey time, which is fairly straight almost all the way. However from there to Exeter it was not possible to get to 125mph easily, and certainly not sustain it, as crossing the Blackdown Hills area and navigating the lower Exe valley sees much more curvature. I get the impression Taunton-Tiverton, which is 100mph, has been absolutely maxed out and could be among the steepest 100mph curves in the country.

The Reading-Taunton line of course has the big obstacle of following the Kennet & Avon canal through much of its eastern half, which leads to some very tight curves between Kintbury and Pewsey. The only way 125mph or anything above 100 is happening there is if the line was redrawn and straightened, which will obviously not happen. Over the Somerset levels is straighter, but then presumably ground conditions are not so good.

 

[30907]

This afternoon I travelled from Uckfield to London Bridge on the hourly DMU.
It runs ‘non stop’ from Oxted to East Croydon missing the 4 station stops served by East Grinstead trains.

It runs down hill from the tunnel just north of Oxted reaching 85 mph.
Then it sits outside South Croydon at the Brighton line Junction for a timetabled four minutes.
This happens on every up Uckfield train for the last three years.

The timetable gives 3 minutes because there is an Up mainline preceding it through South Croydon and a down train passing simultaneously. Why drivers don't factor this in I don't know, but I suspect it is the hope/expectation that other trains will be unpunctual and they will get priority across the junction.
With the complexity of services South of the Thames I would be surprised if this was the only conflict resolved by a pathing allowance - and given that the Uckfield Line is part single track it also allows for slight delays because of that.

 

[hexagon789]

While not in any way a valid test, I have used Train Simulator to drive Bristol to Exeter and done it at 125mph where it's relatively smooth/straight. I only managed to save about 5 minutes from Bristol to Taunton compared to a 30 minute journey time, which is fairly straight almost all the way. However from there to Exeter it was not possible to get to 125mph easily, and certainly not sustain it, as crossing the Blackdown Hills area and navigating the lower Exe valley sees much more curvature. I get the impression Taunton-Tiverton, which is 100mph, has been absolutely maxed out and could be among the steepest 100mph curves in the country.

The Reading-Taunton line of course has the big obstacle of following the Kennet & Avon canal through much of its eastern half, which leads to some very tight curves between Kintbury and Pewsey. The only way 125mph or anything above 100 is happening there is if the line was redrawn and straightened, which will obviously not happen. Over the Somerset levels is straighter, but then presumably ground conditions are not so good.

Even Darlington-York, 44.125mi of which about 42 are 115 or 125, running at 125mph saves only about 4-5 mins depending on traction (ie acceleration).