375 spad

[dave12435]

Just seen on SE Gen that 375607 has passed signal AD679 at danger
According to gen reports the signal was clear as the driver approached but then changed to danger just as he approached it
Apparently the train is now blocking point work
Firstly how the hell did the signal change from a all clear aspect to danger when the signal operator can see the train approaching it?
If the driver has clear aspect he is obviously going to be accelerating so there would be no way to stop for a sudden change like that when hes right on top of it
Secondly where is the loaction of the signal? does the location make it harder to judge the distance
EDIT: AD is Ashford code i believe

 

[ralphchadkirk]

Firstly how the hell did the signal change from a all clear aspect to danger when the signal operator can see the train approaching it?

The signaller may have replaced it in an emergency, it may have been a right-side failure, it may have been the signallers fault.

 

[boing_uk]

It could have been for any number of reasons... no need to get all hysterical about it. :roll:

 

[GB]

before anyone gets excited or jumps to conclusions about whos fault it is, it has been confirmed that there was a fault with a route indicator on AD 679 signal.

 

[ralphchadkirk]

Right side faliure then.

 

[Old Timer]

Storm in a teacup

 

[royaloak]

looks like a big deal if you dont know any different though.

 

[matt]

looks like a big deal if you dont know any different though.

Excellent point, what may seem trivial to some staff who know whats going on it may seem less trivial to a member of the public or an enthusiast who is less knowledgeable on some of the technical aspects of railways.

 

[yorkie]

It could have been for any number of reasons... no need to get all hysterical about it. :roll:

It's nice to be civil about it, and now that the OP knows what sort of reasons can cause this, he can learn that it's not so surprising. Also, who is hysterical anyway? I see no evidence of anyone being hysterical.

 

[chuffchuff]

before anyone gets excited or jumps to conclusions about whos fault it is, it has been confirmed that there was a fault with a route indicator on AD 679 signal.

That is probably "Control Talk" for wrong route set
As the services down here have been FUBAR'd most of the day
AD679 is country end of platform 1

 

[boing_uk]

I never suggested anyone WAS getting hysterical... just that there is no need to.

Although the tone of OP was a bit OTT, with the "Firstly how the hell" like its something major, when it isnt really.

It was a Category B SPAD. A quick google search gives plenty of reasons why a signal could revert to red in front of a moving train. And the second point made in the OP is moot as the OP clearly states the signal reverted to red in front of the train, so judging distance is irrelevent.

It just smacks of sensationalism thats all for a non-event 'tis all, especially when circumstances for such an occurrence can easily be found via a search.

 

[yorkie]

Well, forums could be scrapped on the basis that a search can produce results, but wouldn't that be daft? It's better to answer queries if possible, and if people don't want to discuss it then no need to post.

Thanks to people giving an insight into why these events can happen, the OP now will have a greater understanding.

I agree the tone was slightly sensational but that's probably because the OP has never seen it happen himself or witnessed it. To be fair, it's not extremely common and I'm sure many passengers/enthusiasts have never seen it happen.

 

[O L Leigh]

Firstly how the hell did the signal change from a all clear aspect to danger when the signal operator can see the train approaching it?
If the driver has clear aspect he is obviously going to be accelerating so there would be no way to stop for a sudden change like that when hes right on top of it

What a lot of fuss over nothing.

I've had three signals "go back" on me without warning and I passed two of those because I was going too fast to stop. It gets the old ticker racing when it happens, but really it's no biggy.

O L Leigh

 

[Metroland]

Agree with the above posters a lot of fuss over nothing - now confirmed as a fault.

Signals can get replaced for a number of reasons, sometimes in error, sometimes because points are kicking out or other fault, sometimes in an emergency. Not very nice for the driver, and if the train passes the signal at danger it's known as a 'technical SPAD'.

 

[GB]

That is probably "Control Talk" for wrong route set

It most certainly isnt, if it was a wrong routing it would have stated so.

The fault was a blown lamp.

 

[royaloak]

One blown lamp in the feather wouldnt cause the signal to revert, it only needs 3 working to be "proven".

 

[chuffchuff]

It's a theatre box on that one, takes you to the Dn Hastings and varioius
ways to Dover and Canterbury

 

[royaloak]

Ooops , I take it the Theatre box illuminated, signal cleared THEN the bulb blew putting the signal back. Bit of a bugger really.

 

[dave12435]

Thanks for the asnwers
It has now been confrmed as a signal error rather than driver error
Apparently the driver was already approahing with some speed when it changed
I dont pretend to know that much about signalling in fact i think our systems hugely complucated with some places

 

[ralphchadkirk]

As it says in the thread Dave - it was confirmed as a right side failure a few posts back.

 

[TDK]

It most certainly isnt, if it was a wrong routing it would have stated so.

The fault was a blown lamp.

Was it a colour light signal? If so does it have an SL12 head? The bulbs in the standard head have 2 filaments, if a yellow or a green aspect blow normally the signal will display nothing, not a red.

 

[Barn]

Sounds quite dangerous to me. If the signal is supposed to be single yellow, I think I'd like to know about it!

 

[ralphchadkirk]

Was it a colour light signal? If so does it have an SL12 head? The bulbs in the standard head have 2 filaments, if a yellow or a green aspect blow normally the signal will display nothing, not a red.

It would revert to red, as would any signal if it could not display an aspect. (Unless it was the red one - if which case the driver treats a signal displaying no aspect as displaying a danger aspect.)

 

[NSEFAN]

I presume the signal has TPWS? If so, there's nothing to worry about.

If the driver didn't notice in time then the brake demand would still happen anyways. Quite safe.

 

[Tomnick]

Previous posts suggest that the blown lamp was in the route indicator, not in any of the main aspects.

Surely the purpose of a second filament is to allow the signal to continue operating normally when the first filament goes? When the second one goes too, then I'd have thought that at least the signal in rear would revert to Danger.

 

[GB]

Do theatre box indicators have a first and second filament?
--- old post above --- --- new post below ---

Sounds quite dangerous to me. If the signal is supposed to be single yellow, I think I'd like to know about it!

Not quite sure how you would consider it "dangerous"?

 

[Tomnick]

Not that I'm aware of (my post was referring to TDK's post about first and second filaments in the main aspect). I assume (from the number of theatre indicators around the network with 'gaps'!) that a certain number of lamps are allowed to blow before it'll fail to prove lit, similar to the situation with feathers. Does it make any difference if the signal is already cleared? I think I remember reading somewhere that (in a feather) you need three lamps proved alight in the feather to allow the signal to clear, but it'll then stay cleared as long as there's at least two lamps alight.

 

[royaloak]

On filament heads, when the main filament blows the proving circuit will light the second one up, not as bright and slightly out of focus also a fault light comes on in the signal-box.
Some have both on at the same time though but the rest of it is basically the same.