Signalling irregularity?

[jon0844]

Just been on a train out of King's Cross that came to an abrupt halt leaving platform 10.

It was due to leave at exactly the same time as the train on platform 9 (although arguably it's different in the WTT).

Both of started to leave at the exact same time (give or take). The train on platform 9 was 8-car, we were 4-car. We stopped, the other one didn't.

Immediately the driver came on the PA and said there was a signalling irregularity and had to contact the signaller. Which he must have done (I was sitting in first class and he was talking to someone!) and shortly after a member of staff walked down to have a word, and a minute or two we were on our way.

Now, my initial thought was where do the two tracks merge? Was there ever any risk? Presumably not, as I doubt we'd have been going anywhere and clearly the driver would be aware of the train to his side on the move. However, I'd like to know what DID happen.

 

[IrishDave]

At a guess you were on the 15:44 to Welwyn out of platform 10, and the adjacent train was the 15:44 to King's Lynn from platform 9? If so, the King's Lynn train was booked onto the fast line, and the Welwyn train onto the slow line. They both have a WTT departure time of 15:44.

However, they can depart "in parallel", i.e. it's perfectly safe and permissible to have both signals showing proceed (with 9->DF and 10->DS) at the same time. (Best source I have to hand is this signalling number plan from the King's Cross Simsig.)

So I can only guess that the platform 10 starter suddenly went back to red as the train was departing. (In theory I suppose it's possible that the driver misread and saw the platform 9 starter showing a proceed, but then I would have thought that the station staff shouldn't have given permission for the train to depart...)

 

[ECML180]

Can't find a link and not too knowledgeable on the matter, but I think there was a similar thread recently about trains departing Kings Cross then stopping at the first signal in the tunnel-so close that actually the rear of the train was in the station. Perhaps this was the case and the driver expected a route straight out?

 

[jon0844]

Yes it was that train and we never left the end of platform 10, enabling the dispatcher to walk down and ask what happened. I could hear him, not the driver.

 

[rebmcr]

However, they can depart "in parallel", i.e. it's perfectly safe and permissible to have both signals showing proceed (with 9->DF and 10->DS) at the same time. (Best source I have to hand is this signalling number plan from the King's Cross Simsig.)

Perhaps I'm reading it incorrectly but it appears that it is not possible, from that diagram.

 

[Muzer]

Perhaps I'm reading it incorrectly but it appears that it is not possible, from that diagram.

Seems to me (and my Quail map agrees) that there are diamond crossings unmarked for some reason on that map.

 

[455driver]

Looking at that diagram-
Platform 9 can go from 269 signal straight across to 293 signal on the down fast line.
Platform 10 would be routed from 265 signal to 297 signal om the down slow line.

I think all the funny crossing things are double slips.

 

[scotraildriver]

If a potential SPAD or incident had occurred you wouldn't have left again quickly, as the driver would have been removed for a "chat" with the boss, so must have been an unexpected change of aspect or similar, which the signaller was aware of.

 

[dk1]

Or a passcom activation from someone on the Welwyn who wanted the Lynn

 

[IrishDave]

Looking at that diagram-
Platform 9 can go from 269 signal straight across to 293 signal on the down fast line.
Platform 10 would be routed from 265 signal to 297 signal om the down slow line.

I think all the funny crossing things are double slips.

Sorry - I'm so used to looking at Simsig that I hadn't noticed how odd the diagram actually looks! Yes, the double slips are shown slightly oddly (that's how it looks with all the points locked normal), and 269 to 293 was the route I was intending. 265 to 297 would actually go via 289.

All I was trying to say was there was no danger of collision as they could both be routed out of the station simultaneously.

Come to think of it, perhaps it was a spurious TPWS activation (i.e. the TPWS system falsely fed that the signal was red to the train, and the train thus braked without the driver wanting it to)? Would that fit the bill of "signalling irregularity"?

 

[455driver]

265 to 297 would actually go via 289.

Yes it would, I missed that one!

All I was trying to say was there was no danger of collision as they could both be routed out of the station simultaneously.

Yes I could see that, I was trying to explain how it would work in practise.

Come to think of it, perhaps it was a spurious TPWS activation (i.e. the TPWS system falsely fed that the signal was red to the train, and the train thus braked without the driver wanting it to)? Would that fit the bill of "signalling irregularity"?

Could have been many things including a TPWS, Passcomm, signal flicked back to red etc etc.

 

[jon0844]

Or a passcom activation from someone on the Welwyn who wanted the Lynn

Definitely wasn't that. But we did get delayed at Potters Bar a short while by school kids standing right up to the train when it tried to leave. I could see the monitors and there were a couple of kids messing about as we very slowly crawled away. The driver did ask if someone could move them back, while blasting the horn, but I'm not sure who would have heard him.

Initially I feared trespass and thought it was going to be one of those days. As in I'd let the 1535 fast go to sit in first and do some work, and would now pay the price...

Sent from my D5503 using Tapatalk

 

[A-driver]

You can leave p9 and p10/11 simultaneously, you can't leave 10/11 together though. P9 can access B, C&D road, 10/11 only have access to C&D roads.

It won't have been the driver misreading the p9 signal as you say the dispatcher spoke to him which he wouldn't have do e if he hadn't dispatched the train and also the p9&10 starter signals have blockers on them to prevent misreading as they are so close together. You can't actually see the p9 starter signal from the cab of a 4 car train on 10 because of the boarding.

Most likely it was a simple signal reversion and nothing exciting. They have been having intermittent points problems normally affecting the p8/9 starter signals but there have been issues with p10&11 flashing back to red aswell so I would guess its that (I'm on annual leave at the mo so can't check though).

Also, if the dispatcher was able to speak to the driver from the platform then I assume the signal wasn't passed? Therefore the driver most probably stopped the train, not the TPWS. If it was a simple signal reversion then you would be on the move quickly again. If it just flicked green-red-green as those signals have been doing a bit recently then the driver would stop and report it and the signaller would give permission to proceed.

 

[jon0844]

Thank you. Seems like you've nailed it.

Sent from my D5503 using Tapatalk

 

[D1009]

Come to think of it, perhaps it was a spurious TPWS activation (i.e. the TPWS system falsely fed that the signal was red to the train, and the train thus braked without the driver wanting it to)? Would that fit the bill of "signalling irregularity"?

Probably not. To railwaymen the term signalling irregularity means exactly what it says, an irregularity with the signals, and to my mind it shouldn't be used on the PA. I'd say almost certainly from the OP it would have been a change of aspect.

 

[TDK]

Come to think of it, perhaps it was a spurious TPWS activation (i.e. the TPWS system falsely fed that the signal was red to the train, and the train thus braked without the driver wanting it to)? Would that fit the bill of "signalling irregularity"?

Not a TPWS activation unless the signal had been passed as I cannot think of anywhere there is an OSS leaving a terminal station. A signal irregularity could be anything from a wrong route, wrong aspects being displayed together, a reversion or anything else that is not the norm.

 

[455driver]

I have had the TPWS activate when passing over Aldershot North jn, there arent any grids there!

I suppose it is possible for this to be similar but there are a lot of things more likely to have happened.

 

[High Dyke]

The 2 minute delay at Kings Cross to the Welwyn is unexplained. Another possibility could be that the dispatcher erred when doing dispatch duties. Does the platform use Close Door and Right Away indicators? Did the driver misread the CD indication, close the doors and then attempt to set off, but realised his/her error and stopped? That's when an announcement was made and the dispatcher came for a chat.

All this is supposition on my part, but entirely feasible.

 

[KA4C]

The 2 minute delay at Kings Cross to the Welwyn is unexplained. Another possibility could be that the dispatcher erred when doing dispatch duties. Does the platform use Close Door and Right Away indicators? Did the driver misread the CD indication, close the doors and then attempt to set off, but realised his/her error and stopped? That's when an announcement was made and the dispatcher came for a chat.

All this is supposition on my part, but entirely feasible.

safety critical incident, driver would be lifted

 

[O L Leigh]

It could also be a less experienced driver who has never experienced these two trains departing simultaneously being spooked and stopping thinking that he's had a signalling irregularity. A quick chat to the box to confirm that all is well and the despatcher coming down for a natter to see if everything is OK and away the train goes. I've done it myself on an empty set when it appeared that another train was coming across a junction straight at me. It's always better to stop and ask if you're unsure.

...perhaps.

The point is that we just don't know. There's a lot of speculation, some of it more realistic than others, but we simply can't be certain.

O L Leigh

 

[TDK]

I have had the TPWS activate when passing over Aldershot North jn, there arent any grids there!

I suppose it is possible for this to be similar but there are a lot of things more likely to have happened.

It is possible that something other than the driver stopped the train and a spurious TPWS brake demand is one of them but very unlikely, I think possible the closest guess to this one is the post by O.L. Leigh

 

[455driver]

I think possible the closest guess to this one is the post by O.L. Leigh

yes quite a likely scenario, but we will never know for sure.

 

[TDK]

yes quite a likely scenario, but we will never know for sure.

I think if it was a spurious TPWS activation it would take longer than 2 minutes to complete the RT3188 and all the comms involved. A 2 minute delay is nothing these days

 

[O L Leigh]

There would also be a question over whether or not the unit was fit to continue in service which would take a while.

O L Leigh

 

[A-driver]

It could also be a less experienced driver who has never experienced these two trains departing simultaneously being spooked and stopping thinking that he's had a signalling irregularity. A quick chat to the box to confirm that all is well and the despatcher coming down for a natter to see if everything is OK and away the train goes. I've done it myself on an empty set when it appeared that another train was coming across a junction straight at me. It's always better to stop and ask if you're unsure.

...perhaps.

The point is that we just don't know. There's a lot of speculation, some of it more realistic than others, but we simply can't be certain.

O L Leigh

The 2 minute delay at Kings Cross to the Welwyn is unexplained. Another possibility could be that the dispatcher erred when doing dispatch duties. Does the platform use Close Door and Right Away indicators? Did the driver misread the CD indication, close the doors and then attempt to set off, but realised his/her error and stopped? That's when an announcement was made and the dispatcher came for a chat.



All this is supposition on my part, but entirely feasible.

safety critical incident, driver would be lifted

Was a signal reversion. Is not that uncommon at kings x platforms 8,9,10&11 at the moment, I believe it's something to do with the points. I have reported re versions there before (they happened before I had closed the doors or anything) and the signaller said on both occasions that it is an intermittent fault at that side of the station.