What kind of signal is this?

[t o m]

Hello

I see this signal on the walk to work http://maps.google.co.uk/maps?hl=en&q=rockingham+road&ie=UTF8&ll=52.478905,-0.909327&spn=0,0.019248&z=16&layer=c&cbll=52.478905,-0.909327&panoid=ABE_mqYhUVpogkpe9ZVC5A&cbp=12,216.89,,0,0I noticed that everytime I see it it's on danger, even when trains are passing the signal is still on danger. On the right, you'll have to move the camera, there are some signals over the track at the station, you can also see a HST. I've noticed these signals change when I've been waiting for a train, I know how those ones work. Can anyone enlighten me on the other signal?

Thanks

 

[Zoe]

There is a position light below the main aspect. When this is lit, trains may proceed even when the main aspect is at danger but must be prepared to stop short of any obstruction. The example you posted above would most likely be used to allow trains to run into a platform that is occupied.

 

[swt_passenger]

Looking at the normal aerial view I suspect the signal is there to control the exit from the sidings, and you are possibly seeing trains passing on the main up line, which at that point will be the middle line of the three over the bridge.

 

[GB]

The other signal is just a standard 3 aspect controlled signal with a subsidary and theatre box indicator.

Looking at the arial view its looks like the subsidary signal controls movements into the siding. If this is the case the subsidary signal (when cleared) will show two white lights and the main aspect will remain showing danger. This allows the driver to pass the signal and proceed as far as the line is clear.

Main aspect signals usually only show a proceed aspect untill the train has partly passed it and operated the next track circuit at which point it reverts to danger with the rest of the train still yet to pass.

 

[swt_passenger]

There is a position light below the main aspect. When this is lit, trains may proceed even when the main aspect is at danger but must be prepared to stop short of any obstruction. The example you posted above would most likely be used to allow trains to run into a platform that is occupied.

I think you (and GB) have the orientation wrong - isn't the Google Street View looking south, ie away from the station?

 

[GB]

Looking at the normal aerial view I suspect the signal is there to control the exit from the sidings, and you are possibly seeing trains passing on the main up line, which at that point will be the middle line of the three over the bridge.

I would say this is a more likly explanation as to why it looks like all trains are passing it at danger.

I don't think I have the orientation wrong.

 

[Zoe]

But why would you have a main aspect signal with a theatre to control the exit from sidings?

 

[GB]

The subsidary is controlling the entrance into the siding and the main aspect is protecting the main line. The station is in rear of (on approach to) this signal.

 

[t o m]

Looking at the normal aerial view I suspect the signal is there to control the exit from the sidings, and you are possibly seeing trains passing on the main up line, which at that point will be the middle line of the three over the bridge.

That looks like the right answer to me. I should have looked at the aerial view first really! From the ground it just looks like the train is passing that signal. Also can't believe I've never noticed that's where the siding joins the mainline. Thanks again.

 

[swt_passenger]

I would say this is a more likly explanation as to why it looks like all trains are passing it at danger.

I don't think I have the orientation wrong.

Sorry, I thought when you wrote sidings you meant those alongside the station. I guess you mean the line heading south alongside the main up line, which I wasn't thinking of as a siding, but as the headshunt for the sidings IYSWIM...

 

[GB]

You are right it is a head shunt, I hadn't looked back far enough to see where it actually came from.

 

[Zoe]

So again the question is why a main aspect signal is needed for this. Couldn't a yellow disc or position light have been used?

 

[ralphchadkirk]

So again the question is why a main aspect signal is needed for this. Couldn't a yellow disc or position light have been used?

I would imagine that someone far more knowledgable than you or me has decided that a main aspect is needed. Looking at the aerial photo it looks as if so that a train leaving the sidings can leave on a main aspect, rather than travelling at caution towards the next.

 

[Zoe]

I would imagine that someone far more knowledgable than you or me has decided that a main aspect is needed.

I am not saying it is not correct. I am asking why it is needed.

 

[ralphchadkirk]

I am not saying it is not correct. I am asking why it is needed.

Because someone more knowledgeable than you or me has decided one is needed!

 

[Zoe]

Because someone more knowledgeable than you or me has decided one is needed!

As I said, I am asking why the signal is needed. I am not suggesting that the person that installed it didn't know what they were doing. There has to have been a reason for this decision.

 

[GB]

So again the question is why a main aspect signal is needed for this. Couldn't a yellow disc or position light have been used?

As I say, the main aspect is for movements onto the mainline. Yes you could just use a ground position light with indicator but any trains routed via a GPL would have to travel at caution and prepare to stop at any obstruction or other signal. Proceeding on authority of a mainline aspect removes this need and minimises potential delays.

It may also be the case that when the signal was installed it was installed to specific and then current, standards.

 

[driver9000]

As GB says a main aspect to leave a yard onto a running line is perfectly normal, any movement into the headshunt or neck would be made under the position light with maybe NCK displayed in the theatre box/stencil indicator on the top of the signal head. Having a main aspect to leave the yard allows trains a speedier departure after leaving the sidings over a GPL as they would have to move slowly until picking up sight of the first main aspect.

 

[moggie]

Position Light signal is for the route into the headshunt (or neck).

The Main 3 aspect is for routes onto the main line. Note there appears to be a facing crossover situated just north or Kettering Road bridge hence the theatre route indicator is associated with both main routes to either Up or Down Main. Other signals in the vicinity confirm bi-directional running south of Market Harborough Stn (and north of also if memory serves me correctly).