White City signalling question

[Deleted]

On the EB approach to White City there are two signals, not too far apart. The first signal being approx 5 car lengths before the second. The second signal being immediately before the crossovers to/from the centre track. (Sorry I don't know the signal numbers). Now I've observed trains stopping at the second signal, when the EB platform track is occupied. Which seems to act as the home signal for the EB platform. However, if a train is bound for the centre track, and the centre track is occupied, would trains be held at the first or second signal? Just asking because the second signal is very close the points.

[Deleted]

Might the second signal act as the aspect points signal?

[Deleted]

clavman said:

Whether the middle or E/B roads are occupied or not trains can be drawn up to and held at the second colour light signal. When a train leaves the middle road and the section becomes clear the points can then be switched for that route instead of the normal E/B platform. An arrow on the route indicator tells the driver which road he is being given. The actual inner home signals are BMBs at the beginning of each platform. The first colour light signal is there to hold E/B trains when another train is leaving the siding and is going into the E/B platform. It provides a safe braking distance should it be passed at danger. Trains bound for the middle road or E/B platform can be routed there well in advance of their arrival so long as the sections are clear of other trains at the time.

Thanks for the reply. I'm surprised that a train can draw up so close to points which can change ahead of the train. So the facing points are not taken into account in the overlap distance for the second signal, just the potential fouling points (diamond crossing, trailing points ahead of EB platform, or rear of train in platforms)?

[Deleted]

I would have replied, but seeing as I was out all day, someone has kindly replied on my behalf!

[Deleted]

stephenk said:

Thanks for the reply. I'm surprised that a train can draw up so close to points which can change ahead of the train. So the facing points are not taken into account in the overlap distance for the second signal, just the potential fouling points (diamond crossing, trailing points ahead of EB platform, or rear of train in platforms)?

The points may be close, but they will not change until the locking proves that the train has stopped. Every location has things like this, and thats when backlocks and the like come into play, and of course we all know that if you dont get the backlock up after drawing a train up, you are pretty much in the poo!

[mandgc]

"BMB Signals" (clavman's Reply # 2)

What are these ?

[Deleted]

Block Marker Boards, points in the track which mark the boundaries of unsignalled fixed block sections.

In this case, the colour light signal (WHC 2663, IIRC) is actually the intermediate home signal and the inner junction signal to provide the passenger route to the e/b platform or the middle platform.

[clavman]

theonekea said:

Block Marker Boards, points in the track which mark the boundaries of unsignalled fixed block sections.

In this case, the colour light signal (WHC 2663, IIRC) is actually the intermediate home signal and the inner junction signal to provide the passenger route to the e/b platform or the middle platform.

That's correct if you mean by unsignalled as in regulating and routing. A BMB will not regulate a train's time like a coloured light station starter, but BMB's are treated the same way as coloured lights as they are signals.

[mandgc]

Thank You, clavman (Reply # 8 ) This site gets more exciting every day!!

I am looking forward to the other 299 Weekly Parts of 'Driver's Eye View of the Central Line'

PS - What are the 'chimes' heard halfway along the siding ?

[Deleted]

If it's Liverpool Street siding on the Video 125 DEV you're referring to, these are known as 'confidence tones', and operate every 15 minutes to let the driver know the signal to the L/C is ok.

[clavman]

Confidence tones are broadcast to the entire line every 15 minutes - they sound like your adverage doorbell and as correctly stated tell the driver that the radio to Wood Lane is working ok. The other chimes heard in the video are the ATP chimes telling the driver to slow down as the train is being driven manually. If the chimes go up - go faster!

[Deleted]

clavman said:

theonekea said:

Block Marker Boards, points in the track which mark the boundaries of unsignalled fixed block sections.

In this case, the colour light signal (WHC 2663, IIRC) is actually the intermediate home signal and the inner junction signal to provide the passenger route to the e/b platform or the middle platform.

That's correct if you mean by unsignalled as in regulating and routing. A BMB will not regulate a train's time like a coloured light station starter, but BMB's are treated the same way as coloured lights as they are signals.

Indeed, they are signals, but not the sort that most people would see. I tend to think of them as distinct from a signal, which is a big hunk of metal with bulbs and wires in it.

[Deleted]

This page explains the Central Line signalling system
www.davros.org/rail/signalling/articles/central.html

[rob66]

Had a look around White City depot (Wood Lane) today - It has certainly changed since I see it last. Took a few photos while I was there. I see they have began taking down the sheds (road 13) the road it is said a ghost walks through the train at night. The new depot seems bigger with more roads? Although I didn't go down there but you can see it on the eastbound.

[Deleted]

WoodLanePhil has diagrams of the signal and track layout of the site.