Signals that go OUT

[Deleted]

Every time I pass Hammersmith siding I have seen that some of the signals next to that siding are completely blank. How does that work?

Also, out of curiousity, how many such signals are still in use?

[Deleted]

The signals you refer to are the exit signals from the Barons Court siding.
The signals will illuminate when a train is signalled in the siding, but they remain blank at all other times to prevent confusion due to their close proximity to the other running lines.

Not sure how many more signals are like this on LUL, but there are quite a few on the District which will extinguish the running line signals when the route is set into a bay platform etc.
For example approaching Dagenham East, if the route is set into the bay platform, signal FG22 is blanked out to prevent confusion.

[q8]

The reason for that is, I beleive, that drivers are told NEVER to pass ANY red light and as those signals are next to the main they are arranged to go out in conjunction with the lie of the points at the outlets. A similar situation can be seen at Mansion House, Tower Hill,and Dagenham East when trains are entering the bay. The last signal on the main is arranged to extinguish when the points are set for the bay road.

(You beat me to it by 3 minutes Alan)

[Deleted]

There's another 'pop-up' signal between Baker Street and St John's Wood northbound, which (IIRC) is an auto signal which only illuminates when the train is approaching. Nine times out of ten it was green, and there was plenty of time to react if it was red, but I always wondered why it was a pop-up signal!

Hopefully one of our experts can tell me!
I always assumed it was because the signal was located on a long, uphill straight stretch of line, and only came on at a certain point to prevent the drivers braking too soon. This never worked for me though, because I knew where the signal was and if I didn't see an aspect, I always used to slow down immediately anyway! I'd rather slow down gradually than suddenly see a red light pop-up and have to brake a lot more harshly!

[Deleted]

There used to be pop up signals all over the place. I recall one between Bethnal Green and Liverpool Street WB on the Central, and one between Kennington and Waterloo NB on the Northern. They were there to keep trains moving at line speed, as if they were on drivers would slow down early slowing down the service, they were set so you had just enough sighting time to brake if on, they seem to have gone out of fashion now.

[q8]

There was a pop-up at Aldgate east too. The infamous OB31. At that time it was on the LEFT of the track. It was designed to make you exit the platform quicker and used to pop-up when you put the starter back. Of course drivers soon got the hang of it and it only popped up if it were red. If green it was alight anyway.

Drivers used to say of it "If it's off it's on,. if it's on it's off"

As for the Central, they were all over the blooming place.

Marble Arch, Oxford Circus, Notting Hill Gate..... bleedin' everywhere they were.

[Bill]

Theres one on the crossover at Picc (Bakerloo) its code is A1000. You can see it from either platform. A northbound train will see the blank signal in the 6 foot, the driver will be looking to obey the station starter which is about 2 cars away in the pipe. However when a train is reversing south to north, this signal will illuminate with a danger aspect, once the wrong road starter has cleared if you approach signal A1000 at less than 5mph it will clear to yellow, this process is repeated every few feet until the train has cleared the points as they drop off one by one. Signals BP9, A9000, A9001, A9002. For a normal northbound trip all these will clear to green with the starter, they only show yellows for the reversers to check speed and stop a repeat of a celebrated incident some years ago where a certain driver opened up his train like a tin can on the tunnel wall there!!!

[Tom]

Just the one? ISTR there being a few more... ;D

BTW, the design speed for the speed controlled signals is 11.2mph, just the track movement over the crossover needs the 5mph T(or is it a P?)SR.

[towerman]

There's a pop up signal for the move from Stratford Station to SMD departure road,there's one rusty rail trip a day for this move.Wish I had a £1 for every SPAD they've had there.

[Deleted]

towerman said:

There's a pop up signal for the move from Stratford Station to SMD departure road,there's one rusty rail trip a day for this move.Wish I had a £1 for every SPAD they've had there.

ROFL! You'd have a quid from me then! TW26 was my one and only SPAD back in 2001! ;D

[Bill]

tom said:

Just the one? ISTR there being a few more... ;D

BTW, the design speed for the speed controlled signals is 11.2mph, just the track movement over the crossover needs the 5mph T(or is it a P?)SR.

Can't think of any more. On the Bakerloo? Where???

[Deleted]

So it seems then that they are still in use, even in modern interlockings like TW.

What does the circuit that actually blanks the signal look like?

[Tom]

Bill said:

tom said:

Just the one? ISTR there being a few more... ;D

BTW, the design speed for the speed controlled signals is 11.2mph, just the track movement over the crossover needs the 5mph T(or is it a P?)SR.

Can't think of any more. On the Bakerloo? Where???

I mean more than one collision. Four in thirty years or thereabouts...?

[Tom]

theonekea said:

So it seems then that they are still in use, even in modern interlockings like TW.

What does the circuit that actually blanks the signal look like?

Same lighting circuit but with a down contact of the approach track relays.

[Deleted]

img.photobucket.com/albums/v626/met_apprentice/DSCF2175.jpg

JF21 - Wrong Road Starter at Northwood Northbound, seen when depressed.

There is also A900 which puts the trainstop back up if you are going too fast. However the signal stays green, strange business!!

[Bill]

Oh yeah! My mistake! Yeah, there's been a few derailments and wall strikes at Picc. Occasionally you still see drivers blatantly speeding over points (not there though thanks to the speed control). Madness.

[Harsig]

metapprentice said:

JF21 - Wrong Road Starter at Northwood Northbound, seen when depressed.

I hope it is receiving counselling ;D

[q8]

I hope it is receiving counselling ;D
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That's enough out of you mate! Any more such and I will arrange for you to spend a week in that OTHER control room

[q8]

img.photobucket.com/albums/v626/met_apprentice/DSCF2175.jpg
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In this picture can be seen two double negative rail splays. Now many years ago a train with a low hanging twisted neg shoe caught in one of those and turned both the splays over. Not only that he but blew the breakers out in the sub and took several neg shoes off too before he stopped.

After that they said they were going to remove all such splays on the system. But obviously they did not

[Deleted]

Pop Up Signals - theres another one, at Morden. Just outside tunnel mouth on the N/B road, it only illuminates for trains leaving the centre road, platforms 3 and 4, IIRC. It's been a year or so since I was last down that neck of the woods, so it might 'have been moved or replaced.

[citysig]

metapprentice said:

There is also A900 which puts the trainstop back up if you are going too fast. However the signal stays green, strange business!!

It doesn't actually put it back up. It won't lower until a train has dropped to the correct speed. But it does stay green even with the trainstop up, in order to avoid trains slowing or stopping on the junction.

[Tom]

Now on the subject of A900...
an 'old boy' (who enjoys spending his time in the west country - Citysig and Harsig should know who I mean ) told me that upon commissioning, the first train to run through from Aldgate to Baker St met became front tripped on A900. As the driver applied his rule past it, it lowered.

Confused? Well, A900 is back to back with another signal MB15. The AET who attended the failure found A900's trainstop hose connected to MB15's trainstop, and vice versa.

There were a few red faces considering that didn't show itself up during testing...

[Tom]

metapprentice said:

img.photobucket.com/albums/v626/met_apprentice/DSCF2175.jpg

JF21 - Wrong Road Starter at Northwood Northbound, seen when depressed.

I think you mean suppressed.

If it is depressed, will it notice if I nick it's prozac?

[q8]

If it is depressed, will it notice if I nick it's prozac?
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;D Oh another one asking for sessions in regions of doom.

[Deleted]

looks like someone didnt do a full test then did they

[Tom]

I think what happened was they were giving responses on the GVCRs, and as they were (more or less) functioning it wasn't given a second thought. However had they been giving responses on the trainstops... ;D

[Igelkotten on another computer]

And this is yet anoher example of the cultural differences between Stockholm and London. Over here, in the Metro, any signal that is not lit is to be treated as a failed signal and not to be passed except by following the same procedure as passing a signal a danger. The mere idea of instroducing something like what you have described would probably give our H&S people a heart attack.

I am a bit surprised that LU uses them, especially considering that most of LU drives "on sight", without any form of cab signalling or ATP.

Something similar is used on the mainlines here in Sweden, in the form of "stopplyktor" -single red lights, forming the end points of shunting paths and not normally lit until they are used. Some of these are interlocked with the ATP system used (known as ATC in Swedish btw), some are not. Their use is somewhat controversial, especiallywhen not interlocked with ATC, simply because it is regarded as too easy for a driver to forget that they even exist in a certain place, and thus inadvertently passing them at danger when they are used. When re-signalling or building a completely new are, the use of these SRL are generally discouraged, shunting dwarf signals being preferred instead.

[Dmitri]

Igelkotten said:

And this is yet anoher example of the cultural differences between Stockholm and London. Over here, in the Metro, any signal that is not lit is to be treated as a failed signal and not to be passed except by following the same procedure as passing a signal a danger.

Ditto for the Russian railways and metros: failed signals should be treated as if they are at danger, disused signals are to be crossed out:

[Phil]

Igelkotten said:

Over here, in the Metro, any signal that is not lit is to be treated as a failed signal and not to be passed except by following the same procedure as passing a signal a danger.

And on Network Rail in the UK

[Admin Team]

In answer to both Igelkotten and Dmitri, a signal showing no aspect on London Underground is also normally regarded as a signal remaining at danger.

The exception - at least on the District - is that (as already mentioned) there are a few signals which are suppressed in certain circumstances to avoid any possible misreading, as already described by AlanL and Q8, but the 'action of these signals is well briefed by Instructors in the course of Road Training so drivers know what to expect of them.

I'm pleased to say that we don't have any of the signals described that simply extinguish as you approach them!

In fact I had the situation of a signal showing no aspect only about 10 days ago. The outer home signal to South Ken w/b (EF270A for those interested) was showing no green aspect, and the Station Supervisor at Sloane Square was in attendance to give drivers authority to pass the signal. Sadly, he hadn't been very well briefed - I was given to understand that the signal had failed, not that it was a lamp failure, and it was not until I approached the signal itself that the situation became apparent. Yes, it is a signal at danger and the 'appropriate procedure must be followed, but had I (and I suspect preceeding drivers) been better advised I'm sure that the situation would have been more easily resolved. As it was, a considerable delay to the service had been caused - I arrived at Earls Court at 12:55, having been due to arrive at 12:22, and had been on time until I got caught up in the 'blocking back' caused by the failure.