Signaling and Turnouts at the exit from Tunnels

[scottystitch]

6 minutes ago, Nick C said:

Or make the next one to the right into a single slip? P3 also doesn't need to join onto P4/up main either?

 

I also don't see any way for down trains to enter P2, which is stated to be bidirectionally signalled.

 

While it would obviously depend on the prototype, the trackwork could be simplified a lot whilst still allowing the required moves - please excuse the ASCII-art!

 

------------\
----------\  \
           \  \
-----\      \  \
------x------\  \
       \      \  \
--------`------\--`----------
----------------`------------


------------\
----------\  \
           \  \
-----\   /--\--\
------\-/----\  \
              \  \
---------------\--`----------
----------------`------------

 

You are correct. regarding platform 2.   I've clearly made a change at some point and not changed it back because originally it was a facing crossover in that position.

 

I was trying to avoid the use of slips, but it may come to that.

 

I will go away and try and sort this out. Sorry for wasting anyone's time........

 

Best

Scott

Edited November 27, 2019 by scottystitch

[Nick C]

6 minutes ago, scottystitch said:

Sorry for wasting anyone's time........

 

That's what forums are for It's not a waste of time to me, it's an opportunity to think about how I would do it if it were me...

[scottystitch]

Okay, let's try this again.

 

Down Main now has access to Platforms 1, 2, 5 and 3

 

Up Main has access from Platforms 2, 5, 6, 4 and 7 (Also Platforms 1 and 3, but not directly by design)

 

Platform 7 and the Motorail sidings have no direct access from Down Main, but that's okay, it adds shunting interest; and so access to either of these either from a Down track or an Up track requires at least one reversal.

 

The trailing crossover allows P5 to gain access to the Up Main and allows shunts to/from Platform 1 from/to Platform 7 & Motorail.

 

I've avoided slips.

 

I think this works, but based on my previous post i may have missed something fundamental..........

[TheSignalEngineer]

Not an operationally  friendly layout, for instance to cross a loco from platform 4 to platform 3 blocks all other moves in the throat. You need to consider changing some of the diamonds to slips. 

Consider where you want to make parallel moves and how shunts will be made for example how do you get a loco onto a train which has terminated in a bay.

[The Stationmaster]

It also depends on when the signalling was installed and commissioned and in some respects. by which BR Region.  For example Birmingham Snow Hill is mentioned ina post above as having the signal at the tunnel entrance but in the 1960 resignalling scheme the signal was just north of the tunnel exit (colour light in both cases).   Another factor is the maximum permissible distance between a signal approaching a divergence and the site of the points - in the 1980s this was increased to half a mile but previously it had been much less in order to prevent Drivers accelerating after receiving a proceed aspect for an approach released diverging route.

[TheSignalEngineer]

This was the last mortal remains of the one on the Down Main at Snow Hill. Outside the old part of the tunnel but still in the dark under the station concourse.

In the new layout the signals were put at Moor Street because of the position of the new crossovers in the tunnel. The signal would have to be located in the narrowest part of the original tunnel, only about a train length from Moor Street platform and poor sighting. Better to hold the train in the platform than the tunnel and the following train would still be held at the same place. 

Edited November 27, 2019 by TheSignalEngineer

[big jim]

23 hours ago, Steven B said:

Have a look at Bangor (North Wales); It's plan is simplified version of your track plan. The signal box diagram is about half-way down this page:

http://www.6g.nwrail.org.uk/signallingoverwales.htm

 

Repeaters are used in Belmont Tunnel to help protect the two shunt moves on the down main (into the yard and using the crossover to access the up main). There's a repeater on the entrance to Bangor Tunnel to show the status of the signal at the tunnel exit.

 

Steven B.

bangor was the first place that came to mind when I read the Original question, I’m glad someone else picked up on it too!

 

Couple of things, there is no repeater on the entrance to Bangor tunnel, just a distant signal, the signal on the exit and is mounted on a cantilever gantry is an ‘approach Release’ type IF you are routed to the platform so you will get a yellow ‘caution’ aspect at the distant as you need to be bought down to 15mph, if your going along the down through you can get a green aspect as you can whistle through at 50mph, that very rarely happens though, only ECS, freight etc do it, the last time I did it was on the NMT 

 

the repeaters in Belmont tunnel are off indicators so you can propel (with a guard in communication with you by radio, cab to cab or bell buzzer) out of the tunnel With coaching stock as it’s not advisable to try and change ends in the tunnel, it can be done but you have to get a block on the up line as there is no room on the wall side, I’ve done it a couple of times with IM trains and even knowing nothing is coming it’s bloody scary in there, add to that a 37 belching out fumes and it’s not pleasant! 

Edited November 28, 2019 by big jim

[TheSignalEngineer]

An example of 1962 with a lot of space would be Perth. This is the traffic notice, If you view the PDF at 100% and scroll to the bottom you will find the signalling plan.

 

https://www.s-r-s.org.uk/pullfree.asp?FilePath=ArchiveSignals\Downloads\brscot&FileName=1962-perth.pdf

[scottystitch]

15 hours ago, TheSignalEngineer said:

Not an operationally  friendly layout, for instance to cross a loco from platform 4 to platform 3 blocks all other moves in the throat. You need to consider changing some of the diamonds to slips. 

Consider where you want to make parallel moves and how shunts will be made for example how do you get a loco onto a train which has terminated in a bay.

 

In all honesty I don't want to make shunts and moves too easy, forcing a degree of planning in between arrivals/departures. I had considered that such situations existed on the prototype.

 

Bay 5 and 6 traffic will be exclusively DMU operated.

 

Having said that, along with colour light installation, track rationalisation would probably have occured, so I'm sure you are correct. But wouldn't rationalisation have gone the other way, to remove slips, etc?

 

In any case, the reason for the post was plausibility of signals being in the tunnel. It seems there are many examples. The Tunnel in question on the model will be Hilton, south of Perth in real life, and I see there are signals in there on teh diagram you kindly posted.

 

Best

Scott

[TheSignalEngineer]

From the 1960s rationalisation and resignalling schemes tended to try to eliminate slips where possible.

Replacement of loco hauled trains by DMUs cut down shunting requirements at many locations.  

 

On the revised plan you can't depart from No.5 Bay without coming out via the down to up crossover by the tunnel mouth whish blocks every other move at that end of the station. Getting anything into No.7 Bay is difficult unless it arrives in the Up direction in Platform 2 or 4.

 

A good way of testing a layout is to draw it out at large scale, cut out rectangles of card to represent the rolling stock at the same scale and move it around in the way you are intending to timetable trains and to see if it works. If you tie yourself in a knot you need more flexibility. 

[Steven B]

16 hours ago, big jim said:

Couple of things, there is no repeater on the entrance to Bangor tunnel, just a distant signal, the signal on the exit and is mounted on a cantilever gantry is an ‘approach Release’ type IF you are routed to the platform so you will get a yellow ‘caution’ aspect at the distant as you need to be bought down to 15mph, if your going along the down through you can get a green aspect as you can whistle through at 50mph, that very rarely happens though, only ECS, freight etc do it, the last time I did it was on the NMT

 

I clearly still have a lot to learn! The signalling diagram shows signal R6 at the entrance to Bangot Tunnel on the Down main. I'd assumed that the R ment "Repeat" given that there's a signal 6 at the entrance to the Down platform. Why does the distant not have a unique signal number?

 

Steven B.

 

 

 

[TheSignalEngineer]

In current standards distant signal working automatically will be numbered xxR where xx is the number of the signal it applies to. A distant signal worked by its own lever or switch will have a unique number. 

A banner signal will be numbered xxBR.

Edited November 28, 2019 by TheSignalEngineer
Typo

[scottystitch]

20 hours ago, scottystitch said:

 

 

19 hours ago, TheSignalEngineer said:

 You need to consider changing some of the diamonds to slips. 

 

 

38 minutes ago, TheSignalEngineer said:

  

 

On the revised plan you can't depart from No.5 Bay without coming out via the down to up crossover by the tunnel mouth whish blocks every other move at that end of the station. Getting anything into No.7 Bay is difficult unless it arrives in the Up direction in Platform 2 or 4.

 

 

 

Thanks for considering things further.

 

Okay, so based on your thoughts, if I swap the diamond crossing between platforms 3 and 6 for a double slip and reverse the crossover between 5 and 6, that allows access to 5 and 6 from the down and allows an exit from 5 and 6 directly to the up, via the double slip. it also allows moves between 3 and 4.

 

I'm happy to leave the awkwardness of platform 7 as is.

 

Best

Scott.

[TheSignalEngineer]

1 hour ago, scottystitch said:

 

 

 

Thanks for considering things further.

 

Okay, so based on your thoughts, if I swap the diamond crossing between platforms 3 and 6 for a double slip and reverse the crossover between 5 and 6, that allows access to 5 and 6 from the down and allows an exit from 5 and 6 directly to the up, via the double slip. it also allows moves between 3 and 4.

 

I'm happy to leave the awkwardness of platform 7 as is.

 

Best

Scott.

Will have a look when I finish grandad duty.

[scottystitch]

[TheSignalEngineer]

@scottystitch that's almost what I was doodling this morning. The only thing I had different was if you provide the slip you could save the point end to the bottom right of it and the end of the crossover in bay 5 as long as you don't want to have an arrival in bay 5 simultaneously with a departure from bay 6.

Edited November 28, 2019 by TheSignalEngineer
Typos

[The Stationmaster]

5 hours ago, TheSignalEngineer said:

In current standards distant signal working automatically will be numbered xxR where xx is the number of the signal it applies to. A distant signal worked by its own lever or switch will have a unique number. 

A banner signal will be numbered xxBR.

Ah, a very nice reminder of a discussion I had with a signal engineer on Saturday at the Warley show.  He is working on trying to produce a common set of definitions for signalling terminology and we had a very interesting debate about the use of the term distant signal..

[big jim]

6 hours ago, Steven B said:

 

I clearly still have a lot to learn! The signalling diagram shows signal R6 at the entrance to Bangot Tunnel on the Down main. I'd assumed that the R ment "Repeat" given that there's a signal 6 at the entrance to the Down platform. Why does the distant not have a unique signal number?

 

Steven B.

 

 

 

 

As stationmaster says there is probably a need to get a standard definition in place now signalling has evolved, as a driver I know R on a signal is a distant (or one that can’t display a stop aspect) but its my job to know! 

 

 

[DavidBird]

The UP High Level Goods from Trent had (resignalled from Trent PSB to East Midlands ROC in 2016) TT411 signal immediately south of the exit from Red Hill Tunnel to control the junction into Ratcliffe CEGB power station.

According to the plan, this was a single-lens searchlight signal on a gantry, presumably so that whatever the aspect. it could be seen through the tunnel.

 

 

This is the best photo of the southern portal I've found

https://www.flickr.com/photos/railwaydave/2834813856/in/photolist-5jvaoY-puDmxE-788gbj-26M7rcn-aYCkYV-i2Lpju-XLDN2q-d8Yc1o-FTDviL-WKvyKg-jvyTCv-i2cBt5-9GojfZ-iw3tzT-i2LjfU-qTNnn1-bNC1fz-NSjyKS-24WiV9w-apMRtf-a46F1f-EkbeSu-pdemHZ-23CWLLz-9GojPp-DeXfXm-tBYBGu-jvyFJ1-7pX1w1-6Jscpu-iM8vGE-wwQ5MR-9CZJL1-qTSQ5p-9AStQi-c9Nyfy-qBqDdg-iM8w8j-24WwKCb-GDT5if-chQ5mj-FrwX2V-JASySf-c9NyaG-7zn4XH-7Atyau-ehBzSo-9AVnqf-dXVmbH-7AtySb

but from this photo, it's now a signal on the entrance to the tunnel...
https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&ved=2ahUKEwjZtJjE943mAhWS3eAKHbt5Cq0QjRx6BAgBEAQ&url=https%3A%2F%2Fwww.flickr.com%2Fphotos%2F37260%2F9218951901&psig=AOvVaw1LSvcCD411BG2nvND5jkgr&ust=1575065710265004

Edited November 28, 2019 by DavidBird

[big jim]

Allow me to help....

 

 

 

the signal is still standing, complete with the head bagged up! 

[TheSignalEngineer]

7 hours ago, TheSignalEngineer said:

that's almost what I was doodling this morning.

This was where my doodle got to based on the way that Birmingham New Street tries to fit a gallon into a pint pot outside the PSB.

 

 

It allows straightforward shunt moves between any platforms, options for arriving at five platforms in the Down direction and departing from any platform in the Up direction. As you have space you can have a crossover to get from the Down to Platform 2 rather than the single slip at the bottom

[DavidBird]

9 hours ago, big jim said:

Allow me to help....

 

the signal is still standing, complete with the head bagged up! 

 

Thanks, Jim. That's really helpful.

[WillCav]

13 hours ago, big jim said:

 

As stationmaster says there is probably a need to get a standard definition in place now signalling has evolved, as a driver I know R on a signal is a distant (or one that can’t display a stop aspect) but its my job to know! 

 

 

Hi all

 

There is a standard for how banners and distant signals are named now but there are many still out there that don't comply to modern rules.  I am a signalling designer so I know some of the history etc but others I'm sure can fill in my gaps.

 

Banner repeaters are now #BR where # is the signal they are following.  Previously these could be #R.

 

Distant signals are a different number to the 'home' if they are operated by a different control.  If they just follow the aspects ahead, they can still be #R but we are often asked to rename them during review of schemes.

 

Even in the same signal box area you can get a mixture.

Cambridge has #R & #BR for banners and different number & #R for distants.

 

New distant signals have a plate with the triangle (to represent the semaphore distant notch). Otherwise it could be difficult for a driver as most modern signals have a single aperture.

 

Distants in 4 aspect area could be #RR then #R .

 

Confused yet? I know I am and I'm supposed to understand it...

 

Will

Edited November 29, 2019 by WillCav
Added the last two paragraphs

[scottystitch]

10 hours ago, TheSignalEngineer said:

This was where my doodle got to based on the way that Birmingham New Street tries to fit a gallon into a pint pot outside the PSB.

 

 

It allows straightforward shunt moves between any platforms, options for arriving at five platforms in the Down direction and departing from any platform in the Up direction. As you have space you can have a crossover to get from the Down to Platform 2 rather than the single slip at the bottom

 Thank you. I think I will keep the crossover and keep the diamond as you suggest to minimise the number of slips.

 

Thanks ever so much for your advice.

 

Best

 

Scott

Edited November 29, 2019 by scottystitch
Addition of track plan.

[big jim]

1 hour ago, WillCav said:

New distant signals have a plate with the triangle (to represent the semaphore distant notch)

im nicking that bit of knowledge and passing it off as my own to my trainee drivers!