Trivia: Shortest speed restriction

Status
Not open for further replies.

najaB

Veteran Member
Joined
28 Aug 2011
Messages
25,133
Location
Scotland
What is the shortest speed restriction that you know of? I'm looking for situations where the permitted speed drops and then rises again, as opposed to a series of decreasing/increasing restrictions. This question was prompted by this video, where at approximately 10:20 you can see that the permitted speed drops from 75 to 60 and back to 75 in a very short distance:

I had a look on the sectional appendix and it appears to be one chain:

1589477253181.png

I presume that there's some structure or ground condition reason for it? Does anyone know of any other similar (or shorter!) examples?

(This may have been covered in a previous thread but I couldn't find it in a search)
 
Sponsor Post - registered members do not see these adverts; click here to register, or click here to log in
R

RailUK Forums

Taunton

Established Member
Joined
1 Aug 2013
Messages
6,691
The ECML flat crossing at Newark seems to only be restricted across the crossing itself, brakes seem released just as you get to it and then full power again as soon as clear.
 

LNW-GW Joint

Veteran Member
Joined
22 Feb 2011
Messages
16,217
Location
Mold, Clwyd
There are quite a few locations (like level crossings) where speed restrictions apply for the few yards over the crossing.
Also there's an odd situation on the Cambrian network (ETCS) where there are numerous very short restrictions (over culverts?) which I believe only apply in some sort of degraded signalling mode (speeds posted in km/h).
I remember a 20mph PSR near Craven Arms which applied only to loco-hauled services, over a problematic bridge.
The DMU limit was unchanged (75mph or so), so for passenger trains it only applied to "Gerald", the WG LHCS train. The PSR signs have gone now, as there's no differential.
Between Gobowen and Shrewsbury the line speed has recently gone up to 90mph.
Except for a short stretch where there are 2 level crossings in a short distance (quarter-mile-ish), which is limited to the old 70mph.
Then there's the notorious 60mph at Astley on the Chat Moss line, which interrupts 75mph to the east and 90mph to the west, over just a few hundred yards.
 
Last edited:

Darandio

Established Member
Joined
24 Feb 2007
Messages
9,867
Location
Redcar
I'd imagine there are numerous ones all over the country related to various structures and culverts, certainly where there are differential speeds.
 

Polarbear

Established Member
Joined
24 May 2008
Messages
1,690
Location
Birkenhead
On the Crewe - Chester line, there's a 65mph restriction westbound, on the approach to Beeston Castle, dropping from 90mph. Steps up to 75mph past the box & 90mph from there to the outskirts of Chester.

Not sure how long the 65mph limit is, but it can't be more than a mile along a 21 mile section of line at largely 90mph?
 

sjm77

Member
Joined
8 Jan 2020
Messages
101
Location
Manchester
There is a very short gap in the 90 mph SP differentials approaching Weaverthorpe LC on the down York - Scarborough line. When I used to travel the line regularly it appeared that this is purely to pass the Weaverthorpe distant signal which presumably is not 'distant' enough to allow a safe stop in all conditions from 90 mph + any required safety overlap. It's a moot point if only 185s and C68+MkIV use the line but in the days of 158s I often wondered if drivers slowed down if they could already see the Distant signal had cleared as they approached the speed restriction!

Of course the other peculiarity is the fact that the crossing is called Weaverthorpe which is 5 miles away and not Sherburn which is only half a mile away!

PSR.PNG
 

Ianno87

Veteran Member
Joined
3 May 2015
Messages
15,199
A level crossing north of Roydon has a 55mph restriction just across the level crossing only.
 

yorkie

Forum Staff
Staff Member
Administrator
Joined
6 Jun 2005
Messages
55,806
Location
Yorkshire
Of course the other peculiarity is the fact that the crossing is called Weaverthorpe which is 5 miles away and not Sherburn which is only half a mile away!
Probably to avoid confusion with Sherburn-in-Elmet. I had no idea there was anywhere else in the region called Sherburn.
 

edwin_m

Veteran Member
Joined
21 Apr 2013
Messages
21,796
Location
Nottingham
There used to be a restriction at Matlock Bath for the width of the foot crossing. Not sure if it's still there.

Restrictions at open crossings apply (possibly not always) only to the front of the train, unlike others where the driver can't accelerate until the rear of the train is clear of the restriction. That makes them shorter in some sense.
 

Bald Rick

Veteran Member
Joined
28 Sep 2010
Messages
20,298
Officially, the shortest speed restriction you can have is for 1chain, as per the OP. This is so it can be marked in the official publications. The example in the OP is clearly for the bridge at that point.

Unsurprisingly, there are numerous examples of 1ch restrictions for bridges, culverts and level crossings across the network.
 

hexagon789

Veteran Member
Joined
2 Sep 2016
Messages
12,008
Location
Glasgow
I don't know about the shortest but my 1977 BR Scottish Sectional appendix carries the following about speed restrictions: "where speed restrictions are of less than 12ch. only one mileage is shown, this can be taken as the approximate centre of the restriction".
 

Romsey

Member
Joined
30 Nov 2019
Messages
303
Location
Near bridge 200
Officially, the shortest speed restriction you can have is for 1chain, as per the OP. This is so it can be marked in the official publications. The example in the OP is clearly for the bridge at that point.

Unsurprisingly, there are numerous examples of 1ch restrictions for bridges, culverts and level crossings across the network.

That is because PPS (Possession Planning System) won't accept the start and end mileage as being the same.
 

Crossover

Established Member
Joined
4 Jun 2009
Messages
8,857
Location
Yorkshire
I think there is an open crossing at Burneside which has a 5mph restriction just for the crossing (down from something somewhat higher). I recall that our 185 wasn't very "happy" trying to keep such a low speed!
 

Romsey

Member
Joined
30 Nov 2019
Messages
303
Location
Near bridge 200
For possessions yes, but PPS doesn’t record permanent speed restrictions.


Agreed, PSR's are not published in the WON, but can be created in PPS for time lost calculations in connection with engineering works planning.
TSR's are created in PPS for inclusion in the WON.
Then there are some TSR's which have been there so long (Basingstoke Up Fast / Down Reading) they are likely to be converted to PSR's.....
 

LNW-GW Joint

Veteran Member
Joined
22 Feb 2011
Messages
16,217
Location
Mold, Clwyd
On the Crewe - Chester line, there's a 65mph restriction westbound, on the approach to Beeston Castle, dropping from 90mph. Steps up to 75mph past the box & 90mph from there to the outskirts of Chester.
Not sure how long the 65mph limit is, but it can't be more than a mile along a 21 mile section of line at largely 90mph?

Eastbound it's 75mph, but only for a short stretch through the platforms at Beeston Castle.
West of Chester in the 1990s, speeds were raised from 75mph generally up to 90mph, but 75mph was retained through some station platforms, including Flint.
 

NI 271

Member
Joined
10 Sep 2012
Messages
283
Location
The Doghouse
On the Crewe - Chester line, there's a 65mph restriction westbound, on the approach to Beeston Castle, dropping from 90mph. Steps up to 75mph past the box & 90mph from there to the outskirts of Chester.

Not sure how long the 65mph limit is, but it can't be more than a mile along a 21 mile section of line at largely 90mph?

It's a quarter of a mile, for sighting of the distant. Steps up to 75mph at the distant itself as opposed to by the box.
 

craigybagel

Established Member
Joined
25 Oct 2012
Messages
3,566
I'm always amused and baffled by the down fast through Slade Lane Junction in Manchester. It's 90 from Stockport viaduct to Slade Lane, goes down to 75 over the junction, back up to 90 but only for a quarter of a mile or so before it drops to 65 at Longsite. I can't think of any unit that can go from 75 to 90 to 65 in that space - and the DMUs that I drive would struggle to even power up before it's time to put the brake in for the 65. Not the shortest by any means, but surely one of the most pointless.....


I remember a 20mph PSR near Craven Arms which applied only to loco-hauled services, over a problematic bridge.
The DMU limit was unchanged (75mph or so), so for passenger trains it only applied to "Gerald", the WG LHCS train. The PSR signs have gone now, as there's no differential.

The bridge is still there with a differential - it's now 40/90DMU (the line speed being 90 for everything either side of it). It's actually known to some traincrew as the 40 90 bridge, and it's got a PSR complete with warning boards and AWS magnets (the one on the down is very annoyingly located next to a whistle board, requiring some degree of dexterity to sound the horn and cancel the AWS at the same time). The speed restriction does not apply to Gerald, as there's an exemption that allows 67s and MKIIIs to run at DMU speeds between Shrewsbury and Hereford. Hopefully that will be extended to the MKIVs as well when they eventually enter service.

On the Crewe - Chester line, there's a 65mph restriction westbound, on the approach to Beeston Castle, dropping from 90mph. Steps up to 75mph past the box & 90mph from there to the outskirts of Chester.

Not sure how long the 65mph limit is, but it can't be more than a mile along a 21 mile section of line at largely 90mph?
Eastbound it's 75mph, but only for a short stretch through the platforms at Beeston Castle.
West of Chester in the 1990s, speeds were raised from 75mph generally up to 90mph, but 75mph was retained through some station platforms, including Flint.
It's a quarter of a mile, for sighting of the distant. Steps up to 75mph at the distant itself as opposed to by the box.

From what I was told, originally the entire Crewe - Chester line was 75, including through Beeston in both directions. When the line was upgraded to 90, that's when they discovered that not only was the sighting of the down distant at Beeston too short for 90, it wasn't even good enough for 75 and the limit should have never been that high! And thus the 65 appeared.
 

Tomnick

Established Member
Joined
10 Jun 2005
Messages
5,602
Not sure I've ever heard of a banner for a distant signal. Is it even possible ?
From the Rule Book (signals handbook). Not sure that I’ve ever seen one though! You might as well move the distant signal as go to all the trouble of designing and installing a banner repeater, and I’m not sure it’s even permissible to use a banner repeater to calculate braking distance.

09B5AB60-0CCF-481B-9ECB-08014249B231.jpeg
 

ComUtoR

Established Member
Joined
13 Dec 2013
Messages
7,508
Location
UK
Well blow me down.

Not sure I see the point of a banner for a distant. If the distant was 'on' I'd still wait till the distant before I stuck the brake in, especially if there is a likelihood of the distant stepping up.

Cheers Tommy McTomNick
 

Tomnick

Established Member
Joined
10 Jun 2005
Messages
5,602
Well blow me down.

Not sure I see the point of a banner for a distant. If the distant was 'on' I'd still wait till the distant before I stuck the brake in, especially if there is a likelihood of the distant stepping up.

Cheers Tommy McTomNick
I guess you might’ve found one at a location where it wasn’t possible to achieve the minimum sighting time without using a combination of a banner repeater and the distant signal itself. I’ve found one, sort of, anyway:

https://www.roscalen.com/signals/WestMids/index.htm (scroll down to near the bottom)
 

Llama

Established Member
Joined
29 Apr 2014
Messages
1,914
I'm always amused and baffled by the down fast through Slade Lane Junction in Manchester. It's 90 from Stockport viaduct to Slade Lane, goes down to 75 over the junction, back up to 90 but only for a quarter of a mile or so before it drops to 65 at Longsite. I can't think of any unit that can go from 75 to 90 to 65 in that space - and the DMUs that I drive would struggle to even power up before it's time to put the brake in for the 65. Not the shortest by any means, but surely one of the most pointless.....
Think back to a few decades ago when 'maximum line speed', with restrictions to that line speed, was the norm rather than thinking that every change in permissible speed is there for a reason as it seems to be today. A lot of the older setups are disappearing which confuses new drivers and makes them think that those seemingly odd and very short increases in permissible speed that are left are an oddity.
 

ComUtoR

Established Member
Joined
13 Dec 2013
Messages
7,508
Location
UK
I checked Railsigns and they have been listed as discontinued as of 1992.

Let me go check the Group Standards........ J/K That place is hell.
 

craigybagel

Established Member
Joined
25 Oct 2012
Messages
3,566
Think back to a few decades ago when 'maximum line speed', with restrictions to that line speed, was the norm rather than thinking that every change in permissible speed is there for a reason as it seems to be today. A lot of the older setups are disappearing which confuses new drivers and makes them think that those seemingly odd and very short increases in permissible speed that are left are an oddity.

Ah I see thank you - in that context it does make a bit more sense
 
Status
Not open for further replies.

Top