Speed limit on UK rail network.
Speed limit on UK rail network.
Author
Discussion

Venisonpie

Original Poster:

4,527 posts

106 months

Thursday 5th March 2020
quotequote all
Is there one? For a bit of amusement I downloaded a speed, time and distance app and have been curiously checking speeds when travelling by train.

GNER Azuma reached 127mph but was steady at 124 during the high speed sections between kings x and Leeds.

District line struggles to get above 35mph.

However Avanti West Coast train has just hit 133mph somewhere near Leighton Buzzard which seems a lot?

droopsnoot

14,187 posts

266 months

Thursday 5th March 2020
quotequote all
Yes, there are speed limits, they vary for different types of train and different sections of line. among other things, they're used to decide the position of trigger points for level crossings, to ensure that a train travelling at line speed can (in normal circumstances) trigger the level crossing to close with sufficient advance warning that it doesn't have to slow down.

Flying Phil

1,710 posts

169 months

Thursday 5th March 2020
quotequote all
I believe the maximum speed is 125mph in general (HS1 to the Channel Tunnel is higher 180??) and that is due to the signalling constraints. Obviously there are many sections with lower speed limits as signified by lineside signs. Quite a few of the newer trains are good for 140 though.

itcaptainslow

4,524 posts

160 months

Thursday 5th March 2020
quotequote all
The limit for line side, four aspect signalling (as found on much of the faster sections of the UK mainline) is 125mph. HS1 is higher due to in cab signalling.

The line speed itself varies all over the UK, and is set on, but not limited to;
-Signalling spacing, sighting, 2/3/4 aspect sequences (basically how far back a driver will be informed there is a red signal ahead), type of signalling (semaphore or colour light)
-If there is any track mounted safety equipment such as TPWS or ATP
-Gradients and curvature
-Track/overhead line condition and maintenance
-Type of traction (trains) that use the route
-Type of line (goods or passenger)
-Any particular route characteristics or risks (e.g. it being a known low adhesion spot or level crossing sighting issues)
-Frequency of traffic

There is no “unrestricted” section of line to my knowledge in the UK.

nc107

476 posts

232 months

Thursday 5th March 2020
quotequote all
The notional speed limits (Permitted Line Speed) vary greatly between the different lines. You can find them all here:

https://www.networkrail.co.uk/industry-and-commerc...

Scroll down and each area has it's own SA - open one and scroll down until you come to the diagrams and you will see they have figures on each of the lines; these are the respective speed limits at each chainage.

To complicate matters different train types can have higher or lower speed limits than the PLS depending on where they are running, what their consist is, and what type of train they are.

Examples:
A Pendalino can run on some sections of notionally 110mph track at 125 (known as Enhanced Permissible Speed) as it has tilt,
A Class 185 has to run at a lower than PLS on certain sections because it is too heavy (track damage).
An HST with 9 coaches can run at PLS but an HST with 4 coaches must run at a lower speed as it doesn't have enough braking to stop within the notional braking envelope assumed by PLS.
An electric train running on the fast down to St Pancras can't go above 100mph even though the track is 125mph. That is because the OLE is only certified to 100mph.

There are many more!

matchmaker

8,969 posts

224 months

Thursday 5th March 2020
quotequote all
nc107 said:
The notional speed limits (Permitted Line Speed) vary greatly between the different lines. You can find them all here:

https://www.networkrail.co.uk/industry-and-commerc...

Scroll down and each area has it's own SA - open one and scroll down until you come to the diagrams and you will see they have figures on each of the lines; these are the respective speed limits at each chainage.

To complicate matters different train types can have higher or lower speed limits than the PLS depending on where they are running, what their consist is, and what type of train they are.

Examples:
A Pendalino can run on some sections of notionally 110mph track at 125 (known as Enhanced Permissible Speed) as it has tilt,
A Class 185 has to run at a lower than PLS on certain sections because it is too heavy (track damage).
An HST with 9 coaches can run at PLS but an HST with 4 coaches must run at a lower speed as it doesn't have enough braking to stop within the notional braking envelope assumed by PLS.
An electric train running on the fast down to St Pancras can't go above 100mph even though the track is 125mph. That is because the OLE is only certified to 100mph.

There are many more!
Certainly are! The Scotland Zone Sectional Appendix alone is 1071 pages long...

Venisonpie

Original Poster:

4,527 posts

106 months

Thursday 5th March 2020
quotequote all
nc107 said:
The notional speed limits (Permitted Line Speed) vary greatly between the different lines. You can find them all here:

https://www.networkrail.co.uk/industry-and-commerc...

Scroll down and each area has it's own SA - open one and scroll down until you come to the diagrams and you will see they have figures on each of the lines; these are the respective speed limits at each chainage.

To complicate matters different train types can have higher or lower speed limits than the PLS depending on where they are running, what their consist is, and what type of train they are.

Examples:
A Pendalino can run on some sections of notionally 110mph track at 125 (known as Enhanced Permissible Speed) as it has tilt,
A Class 185 has to run at a lower than PLS on certain sections because it is too heavy (track damage).
An HST with 9 coaches can run at PLS but an HST with 4 coaches must run at a lower speed as it doesn't have enough braking to stop within the notional braking envelope assumed by PLS.
An electric train running on the fast down to St Pancras can't go above 100mph even though the track is 125mph. That is because the OLE is only certified to 100mph.

There are many more!
Blimey, plenty to consider then.

So my chappie doing 133mph this morning in a pendolino may be within the limit if the line was rated 125mph but this particular train can run higher?

matchmaker

8,969 posts

224 months

Thursday 5th March 2020
quotequote all
Venisonpie said:
nc107 said:
The notional speed limits (Permitted Line Speed) vary greatly between the different lines. You can find them all here:

https://www.networkrail.co.uk/industry-and-commerc...

Scroll down and each area has it's own SA - open one and scroll down until you come to the diagrams and you will see they have figures on each of the lines; these are the respective speed limits at each chainage.

To complicate matters different train types can have higher or lower speed limits than the PLS depending on where they are running, what their consist is, and what type of train they are.

Examples:
A Pendalino can run on some sections of notionally 110mph track at 125 (known as Enhanced Permissible Speed) as it has tilt,
A Class 185 has to run at a lower than PLS on certain sections because it is too heavy (track damage).
An HST with 9 coaches can run at PLS but an HST with 4 coaches must run at a lower speed as it doesn't have enough braking to stop within the notional braking envelope assumed by PLS.
An electric train running on the fast down to St Pancras can't go above 100mph even though the track is 125mph. That is because the OLE is only certified to 100mph.

There are many more!
Blimey, plenty to consider then.

So my chappie doing 133mph this morning in a pendolino may be within the limit if the line was rated 125mph but this particular train can run higher?
If he was doing 133mph he could well get a Form 1 ("Please explain...") as the EPS at Leighton Buzzard is 125mph!

Venisonpie

Original Poster:

4,527 posts

106 months

Thursday 5th March 2020
quotequote all
matchmaker said:
Venisonpie said:
nc107 said:
The notional speed limits (Permitted Line Speed) vary greatly between the different lines. You can find them all here:

https://www.networkrail.co.uk/industry-and-commerc...

Scroll down and each area has it's own SA - open one and scroll down until you come to the diagrams and you will see they have figures on each of the lines; these are the respective speed limits at each chainage.

To complicate matters different train types can have higher or lower speed limits than the PLS depending on where they are running, what their consist is, and what type of train they are.

Examples:
A Pendalino can run on some sections of notionally 110mph track at 125 (known as Enhanced Permissible Speed) as it has tilt,
A Class 185 has to run at a lower than PLS on certain sections because it is too heavy (track damage).
An HST with 9 coaches can run at PLS but an HST with 4 coaches must run at a lower speed as it doesn't have enough braking to stop within the notional braking envelope assumed by PLS.
An electric train running on the fast down to St Pancras can't go above 100mph even though the track is 125mph. That is because the OLE is only certified to 100mph.

There are many more!
Blimey, plenty to consider then.

So my chappie doing 133mph this morning in a pendolino may be within the limit if the line was rated 125mph but this particular train can run higher?
If he was doing 133mph he could well get a Form 1 ("Please explain...") as the EPS at Leighton Buzzard is 125mph!
Interesting as the return journey maxed at 129mph around Hemel Hempstead.

wolfracesonic

8,920 posts

151 months

Thursday 5th March 2020
quotequote all
nc107 said:
The notional speed limits (Permitted Line Speed) vary greatly between the different lines. You can find them all here:

https://www.networkrail.co.uk/industry-and-commerc...

Scroll down and each area has it's own SA - open one and scroll down until you come to the diagrams and you will see they have figures on each of the lines; these are the respective speed limits at each chainage.

To complicate matters different train types can have higher or lower speed limits than the PLS depending on where they are running, what their consist is, and what type of train they are.

Examples:
A Pendalino can run on some sections of notionally 110mph track at 125 (known as Enhanced Permissible Speed) as it has tilt,
A Class 185 has to run at a lower than PLS on certain sections because it is too heavy (track damage).
An HST with 9 coaches can run at PLS but an HST with 4 coaches must run at a lower speed as it doesn't have enough braking to stop within the notional braking envelope assumed by PLS.
An electric train running on the fast down to St Pancras can't go above 100mph even though the track is 125mph. That is because the OLE is only certified to 100mph.

There are many more!
Interesting, so a coach with 9 coaches can stop in a shorter distance than one with 4, all the additional braking outweighing the extra weight of the coaches/passengers, correct?

nc107

476 posts

232 months

Thursday 5th March 2020
quotequote all
Yes, the class 43 HST power cars have a lot of power but when in a consist they rely on the coaches to provide the necessary braking so that stopping distances remain acceptable.

regarding the Pendolino..I assume he was "making up time", Mr Supervisor Sir smile

P5BNij

15,875 posts

130 months

Thursday 5th March 2020
quotequote all
nc107 said:
The notional speed limits (Permitted Line Speed) vary greatly between the different lines. You can find them all here:

https://www.networkrail.co.uk/industry-and-commerc...

Scroll down and each area has it's own SA - open one and scroll down until you come to the diagrams and you will see they have figures on each of the lines; these are the respective speed limits at each chainage.

To complicate matters different train types can have higher or lower speed limits than the PLS depending on where they are running, what their consist is, and what type of train they are.

Examples:
A Pendalino can run on some sections of notionally 110mph track at 125 (known as Enhanced Permissible Speed) as it has tilt,
A Class 185 has to run at a lower than PLS on certain sections because it is too heavy (track damage).
An HST with 9 coaches can run at PLS but an HST with 4 coaches must run at a lower speed as it doesn't have enough braking to stop within the notional braking envelope assumed by PLS.
An electric train running on the fast down to St Pancras can't go above 100mph even though the track is 125mph. That is because the OLE is only certified to 100mph.

There are many more!
On the freight side there are additional speed limits on certain wagons passing over certain bridges, for instance if I'm on the Up Slow at Wolverton with a loaded train of high sided stone wagons I have to slow right down from 60mph to 10mph for the truss girder bridge over the canal, just south of the station, which means getting back up to my maximum of 60mph again can take some time. On a good day with clear signals I can get back up to that speed by the long straight just south of Bletchley. There are many, many specific locations like this example all over the network where a 60mph freight can be brought down to 5, 10, 15 or 20mph for very short sections of line, simply because the Engineers have decreed that the underlying structure of a particular bridge built in the Victorian era can't take the strain of the heavier trains we now operate at higher average speeds.

There are some odd speed restrictions here and there which apply because of limited clearances under bridges, an example on one of my regular routes is the Victorian arched overbridge at Oakley, a few miles north of Bedford on the Midland Mainline - on the Up Slow line we're restricted to 20mph there as high sided wagons moving any faster than that will move out of gauge slightly, hitting the brickwork on the left hand side as you pass beneath it. All of these speed restrictions are part of our route knowledge which we have to learn off by heart before being allowed to work the routes in question.

velocemitch

4,019 posts

244 months

Thursday 5th March 2020
quotequote all
Back in my train spotter days I went to visit the Western region the first year the HST’s were introduced.
The drivers seemed to have a very liberal view of the speed limit then. I clocked one at constant 137mph the old fashioned way using a stopwatch over the mile posts.

I believe they clamped down heavily on it shortly after.


Bizzarly the microwave in the buffet car was another highlight of those trips for me!

MitchT

17,089 posts

233 months

Thursday 5th March 2020
quotequote all
The Inter-City 225 sets launched in 1989 are capable of 140mph (225km/h, hence the name) but don't go faster than 125 in service.

itcaptainslow

4,524 posts

160 months

Friday 6th March 2020
quotequote all
velocemitch said:
Back in my train spotter days I went to visit the Western region the first year the HST’s were introduced.
The drivers seemed to have a very liberal view of the speed limit then. I clocked one at constant 137mph the old fashioned way using a stopwatch over the mile posts.

I believe they clamped down heavily on it shortly after.


Bizzarly the microwave in the buffet car was another highlight of those trips for me!
There’s a section of the East Coast Mainline near Grantham that has a fifth aspect-a flashing green. This was used in testing the IC225 sets and also for setting a (still held) diesel traction speed record with a HST-just shy of 150mph, if memory serves!

Venisonpie

Original Poster:

4,527 posts

106 months

Friday 6th March 2020
quotequote all
P5BNij said:
On the freight side there are additional speed limits on certain wagons passing over certain bridges, for instance if I'm on the Up Slow at Wolverton with a loaded train of high sided stone wagons I have to slow right down from 60mph to 10mph for the truss girder bridge over the canal, just south of the station, which means getting back up to my maximum of 60mph again can take some time. On a good day with clear signals I can get back up to that speed by the long straight just south of Bletchley. There are many, many specific locations like this example all over the network where a 60mph freight can be brought down to 5, 10, 15 or 20mph for very short sections of line, simply because the Engineers have decreed that the underlying structure of a particular bridge built in the Victorian era can't take the strain of the heavier trains we now operate at higher average speeds.

There are some odd speed restrictions here and there which apply because of limited clearances under bridges, an example on one of my regular routes is the Victorian arched overbridge at Oakley, a few miles north of Bedford on the Midland Mainline - on the Up Slow line we're restricted to 20mph there as high sided wagons moving any faster than that will move out of gauge slightly, hitting the brickwork on the left hand side as you pass beneath it. All of these speed restrictions are part of our route knowledge which we have to learn off by heart before being allowed to work the routes in question.
That sounds bloody frustrating.

Truckosaurus

12,940 posts

308 months

Friday 6th March 2020
quotequote all
Also, I assume trains don't always go at the speed limit but at a set speed depending on its timetable, as my commuter train definitely speeds up if it is running behind schedule.

nc107

476 posts

232 months

Friday 6th March 2020
quotequote all
My background, many moons ago, was powertrain design and performance simulations in rail. It used to be the case, and I suspect still is, that trains were specified for a desired line speed (say 90 mph) but specified and designed to +10%(99mph) of that line speed. We would test to the+10%. This is because if the max line sped was the balancing speed (tractive effort available - resistance) you would slow down on any slight incline or any meaningful headwind. All of which would play havoc with any attempt at regulating a timetable. Of course, with a following wind, auxiliaries off and wing mirrors folded in it was occasionally possible to go a bit faster......your honour smile

Edited by nc107 on Friday 6th March 10:19

Venisonpie

Original Poster:

4,527 posts

106 months

Friday 6th March 2020
quotequote all
nc107 said:
My background, many moons ago, was powertrain design and performance simulations in rail. It used to be the case, and I suspect still is, that trains were specified for a desired line speed (say 90 mph) but specified and designed to +10%(99mph) of that line speed. We would test to the+10%. This is because if the max line sped was the balancing speed (tractive effort available - resistance) you would slow down on any slight incline or any meaningful headwind. All of which would play havoc with any attempt at regulating a timetable. Of course, with a following wind, auxiliaries off and wing mirrors folded in it was occasionally possible to go a bit faster......your honour smile

Edited by nc107 on Friday 6th March 10:19
What is tractive effort as opposed to BHP or torque?

nc107

476 posts

232 months

Friday 6th March 2020
quotequote all
BHP = Tractive effort x speed

Tractive effort is the force available (or required) to move something

This gives a pretty good explanation