Signalling question

[Islineclear3_1]

My memory is very hazy on this, but my question relates to how a red and yellow lever in a signal box operates a semaphore outer home and distant signal mounted on the same post.

If the outer home is pulled off, how does the distant signal operate? I get that it does not operate/clear if the next home signal in advance is at danger.

Specifically, this relates to the approach to Horsted Keynes in the "UP" direction where there are 2 distants on the approach. The first is "linked" to the outer home signal up the line (as they share the same lever number in the box), whilst the second distant is mounted on the same post as the outer home and is operated by a different lever

 

[Tester]

My memory is very hazy on this, but my question relates to how a red and yellow lever in a signal box operates a semaphore outer home and distant signal mounted on the same post.

If the outer home is pulled off, how does the distant signal operate? I get that it does not operate/clear if the next home signal in advance is at danger.

Assuming that it is mechanical (i.e. not motor worked) it will be slotted.

In other words mechanical levers at the bottom of the post are arranged so that the distant will only clear with both levers pulled - simple but effective!

 

[SECR 65]

Horsted Keynes is a bit complicated!

I'm not sure if you know the details of the signalling system or not?...

Unfortunately, I'm not a signalman (at least currently), so I don't know for certain!

One of the outer distants (not sure if it's up direction at Caseford Bridge or down direction at Horsted House Farm Bridge, or both) only works if a train is going into platform 3.

Apparently in the down direction 4/5 has approach control, but not the other platforms.

I know lots of people who are signallers at the Bluebell, so I can ask any specific questions you have.

Up trains used to normally have a clear road into HK, as they used to use platform 3 (and down trains in 2, where the road can be set into Ardingly, hence the overlap works.)

Now, for reasons which understand but personally aren't a massive fan of, up trains use 2 and downs 3. From 3 going down the only route is to Sheffield Park on the single line, so up trains get checked at Three Arch Bridge until the down is stationary (or a long way off).

 

[Islineclear3_1]

Horsted Keynes is a bit complicated! I know lots of people who are signallers at the Bluebell, so I can ask any specific questions you have.

Thank you. So, in the Up Direction just before 3-arch bridge is a home and a distant mounted on the same post. According to the signalling diagram; the home is lever no. 40 in the box and the distant is no. 38. There is also another distant in the rear which is lever no. 40 in the box. Hence the actual lever is painted red (upper) and yellow (lower). I am interested in how this works so that I can caption up my photograph accurately.

 

[John Webb]

A single lever painted both Red and Yellow is installed to operate what's known as an 'Intermediate Block signal' (IBS). These were installed often when a small box closed but there was need to maintain the section to enable trains to run to the timetable. It was usual for the signals to be motor-worked or to be a home and distant colour light signal.

I haven't seen the diagram for Horsted Keynes, but it would seem 40 is the first (outer?) home, probably mechanically worked, and the distant in the rear of it possibly motor-worked from contacts on the home signal.
Distant 38 presumably refers to the next home (inner?) signal. But as 38 mustn't come off unless the 40 Stop signal is cleared, there is a 'slotting' arrangement to prevent this.
So the two-colour lever is not working the two signals on the same post.
Hope this makes sense!

 

[SECR 65]

Ok as it seems to be relevant I'll explain the long section working (LSW) arangement on the Bluebell to the best of my knowledge:

Sheffield Park and Kingscote box generally need to be staffed to run trains along the full length of the line. (Side note: I think somehow Kingscote can be switched out, but in practice there is always a signaller on duty when trains are running to there.)

Horsted Keynes can be switched out and this happens fairly regularly. This means the railway in effect runs as a long section between Sheffield Park and Kingscote, with a completely seperate token system (think it's green or is it yellow!?...)

Long section working only works through Horsted Keynes platform 3. (So when it's a one-train service using, say platform 4/5 at HK, the box there must be staffed.) I think, as is explained in post 4, the outer distants are used in LSW, but I believe they also work when running through platform 3 in short section mode.

Horsted Keynes running line signals, south to north (sorry I don't know the numbers):

• Up outer distant (Caseford Bridge)
• Up outer home + up inner distant (3-Arch Bridge)
• Down advanced starter (New Road Bridge)
• Up inner home with dot matrix route indicator (adjacent to down yard)
• Down platform starting signals (1 is Ardingly only, 2 is AY/SP with two seperate semaphore arms, 3 is SP only, 4/5 is SP or down yard with dot matrix route indicator)
• Up platform starting signals (1 is via the loop, 2 is via the loop, 3 is via the main (usually) or the loop using dummy 13 (two seperate semaphore arms), 4/5 is via the main)
• Up 1st advanced starters (one for the main, one for the loop) (Leamland Bridge)
• Down inner home with dot matrix route indicator (1/2/3/3L/4) (Leamland Junction)
• Up 2nd advanced starter (Horsted House Farm Crossing)
• Down outer home + down inner distant (has a repeater at the top of post - for visibility I think) (Horsted House Farm Bridge)
• Down outer distant (between Black Hut and Vaux End)

In the up direction it's typical to have a "clear run" through the station, apart from the above mentioned running with the 'platforms swapped'.
In the down direction I think 4/5 has approach control, and on the other platforms I believe the signaller has to manually clear each signal as the train approaches.

 

[Rescars]

I am sure there are very sound reasons for this, but isnt it a bit unusual to have an outer distant for the outer home and a second inner distant for the inner home? IIRC a long time ago there were north and south boxes at HK. Would there have been inner distants worked by the other box back then?

 

[Kentish RYS]

Inner Distants (also called somthing like acceleration distants) while not common on basic layouts everywhere were not rare. The Great Central has them on the double track bit as I think was LNER(GC) practice. They are useful if you slow a train at the distant but then the line clears the driver can accelerate as they know there is not other signals at red. Helpful following something or waiting for a train in the opposite direction to get in a loop/yard clear of the line. The usefulness obviously depends on layout and traffic patterns.

 

[Rescars]

Post deleted

 

[Islineclear3_1]

Thank you all for your kind help; a very interesting insight.

So, if No. 40 lever is pulled off to clear the Up Main Outer Home, does No. 40 distant (in the rear) automatically clear? Then, when No. 37 lever is pulled off to clear the Up Main Inner Home, does No. 38 distant (on the same post as No. 40 at 3-arch bridge) clear or can this only happen if all the Up signals are pulled off?

 

[SECR 65]

I had it explained to me somewhat today by a signaller who signs HK box - did I understand it all???... no...

In the up direction, there's a two minute delay from resetting the outer home to danger from being able to pull off the inner home (I think this only applies if the track circuits don't activate - i.e. track inspection trolley etc.)

In the down direction, 4/5 and 3 via the loop have automatic approach control. The other roads need manual approach control by the signaller.

Then, when No. 37 lever is pulled off to clear the Up Main Inner Home, does No. 38 distant (on the same post as No. 40 at 3-arch bridge) clear or can this only happen if all the Up signals are pulled off?

I think that the up inner distant will only work if the road through the station is set through platform 3 via the main. This is a semi-guess, but that the lever which controls it is in effect a prerequisite for switching the box into long section working.

 

[Rescars]

HK signalling seems to have a lot going on. Did I see somewhere that some part of the layout involves the use of Sykes Lock and Block?