Signal box failure - theoretical question

[ComUtoR]

Speak for yourself, we still have AB and semaphores down here!

Can't remember the last time I drove through semaphore. We do have some weird colour light AB. They upgrade the semaphores to colour light but kept the AB and signal boxes. Haven't been down there for a while and I think it got re-signalled but I couldn't say to what.

I still find AC strange. Generally I'm DOO/DC/TCB. You country bumpkins need to join the 21st century. Computers are awesome and never break....

 

[Llanigraham]

What I was actually hoping for was a run through of how the pen and paper method actually works when the panels are down and the signaller cannot "see" the trains the location of the trains under his control.

Hoping the signaller who experienced it will see and be kind enough to share.

The nearest I can get to is the complete failure of one of my Block Instruments (AB Box) where we ran everything through the section from telephone calls between the 2 Boxes, TRB entries, and phone calls to the drivers to authorise passing signals at danger. Delay minutes were vast!!

The same could be done on a Panel, but I wouldn't want to be the poor sod doing it!!

 

[Llanigraham]

Speak for yourself, we still have AB and semaphores down here!

But even that can go wrong!!
(see above)

 

[455driver]

But even that can go wrong!!
(see above)

How many signalling problems has Cornwall had in the last month?
How many signalling problems has Slough area had in the last month?

 

[Tomnick]

The aforementioned ROC-in-a-Box™.

If you can call a portakabin with a desk, whiteboard, diagram, magnetic stickers and a phone a ROC...yup .

 

[najaB]

If you can call a portakabin with a desk, whiteboard, diagram, magnetic stickers and a phone a ROC...yup .

Ah, that would be Diet ROC-in-a-Box™ then.

 

[Sunset route]

What I was actually hoping for was a run through of how the pen and paper method actually works when the panels are down and the signaller cannot "see" the trains the location of the trains under his control.

Hoping the signaller who experienced it will see and be kind enough to share.

In this one type of failure I will explain, but this will not cover all scenario.

Example a TDM indication failure. A TDM is a method of sending instructions from a signalling centre (control circuit), and receiving information back about the status of the signalling systems (indication circuit) from the remote relay room.

If your TDM indication circuit fails you will get an audible alarm and a panel indications showing that's it's failed, with all the track circuits and points for that interlocking showing occupppied and flashing out of correspondence. Anybtrains wothon that area have now disappeared from from your diagaram as it has flooded red. The train driver sees nothing as all the signalling is functionin normal, it's just the signaller can't see that.

After taking stock of what routes have been set and a rough idea of where the trains are, the signaller can switch in the Override system which is FDM based and switches most route to straight running, but if the override comes as Auto/selective it will also allow you to set some basic routes, note that all routes will not be covers just a limited amount.

The buttons that you you to set routes are not part of the main NX panel but a separate group on their own. They will have a set of free lights next to them. When these lights are illuminated the associated button can be pressed to set a route, and by default any free lights that are not illuminated can not be used to set routes.

The train describer will only work in a few selected TD berths so between that and the free lights on the override route selecting buttons is your only indication where trains are.

You have to keep your wits abbout you but you can still signal trains even without knowing exactly where they are. Not a nice experience first time round but you get used to it after a few failures.

Now a Remote control (RC) failure where there is no communication between signal cantre and remote relay room which also cause all the outside signalling equipment to fail as well as giving you both TDM control & indications failure, will stop the job until a) the techs fix it, or b) you can find a small orange army of staff to start securing evething to move all the trapped trains.

While your waiting for that to happen your just using the radio and SPTs to talk to every train driver to confirm location as all the track circuits for whole interlocking area will be showing red, which will sometimes step a train description into the next berth while the train itself will still be at the signal in rear and telling them not to move while writing all of their location details down on good old fashioned paper. The same goes if your local power your panel fails (panel is completely dead and dark) or your CBI such as smartlock fails as well (everything show red as well). Then its game over.

 

[tygar2]

In this one type of failure I will explain, but this will not cover all scenario.

Example a TDM indication failure. A TDM is a method of sending instructions from a signalling centre (control circuit), and receiving information back about the status of the signalling systems (indication circuit) from the remote relay room.

If your TDM indication circuit fails you will get an audible alarm and a panel indications showing that's it's failed, with all the track circuits and points for that interlocking showing occupppied and flashing out of correspondence. Anybtrains wothon that area have now disappeared from from your diagaram as it has flooded red. The train driver sees nothing as all the signalling is functionin normal, it's just the signaller can't see that.

After taking stock of what routes have been set and a rough idea of where the trains are, the signaller can switch in the Override system which is FDM based and switches most route to straight running, but if the override comes as Auto/selective it will also allow you to set some basic routes, note that all routes will not be covers just a limited amount.

The buttons that you you to set routes are not part of the main NX panel but a separate group on their own. They will have a set of free lights next to them. When these lights are illuminated the associated button can be pressed to set a route, and by default any free lights that are not illuminated can not be used to set routes.

The train describer will only work in a few selected TD berths so between that and the free lights on the override route selecting buttons is your only indication where trains are.

You have to keep your wits abbout you but you can still signal trains even without knowing exactly where they are. Not a nice experience first time round but you get used to it after a few failures.

Now a Remote control (RC) failure where there is no communication between signal cantre and remote relay room which also cause all the outside signalling equipment to fail as well as giving you both TDM control & indications failure, will stop the job until a) the techs fix it, or b) you can find a small orange army of staff to start securing evething to move all the trapped trains.

While your waiting for that to happen your just using the radio and SPTs to talk to every train driver to confirm location as all the track circuits for whole interlocking area will be showing red, which will sometimes step a train description into the next berth while the train itself will still be at the signal in rear and telling them not to move while writing all of their location details down on good old fashioned paper. The same goes if your local power your panel fails (panel is completely dead and dark) or your CBI such as smartlock fails as well (everything show red as well). Then its game over.

Thanks Sunset route. That post was absolute gold. [emoji122] [emoji122]

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[Sunset route]

Thanks Sunset route. That post was absolute gold. [emoji122] [emoji122]

Sent from my SM-G935F using Tapatalk

It's a shame I didn't proof read out some of the typo's lol

 

[33056]

One particular event from around 25 years ago sticks in my mind though it was planned and not an emergency scenario.

The CEGB needed to do some work on the power suppy meaning that the power to the actual panel needed to be turned off although the domestic supply for things like the light and the kettle (most important!) was not affected. This affected some 24 1/2 miles of four track mainline, two of which would be under engineers possession albeit with no work sites within, and trains running along the remaining two which were to be split up into two block sections.

The time chosen was a Sunday night as that was the quietest night of the week, details are a bit hazy now but I seem to recollect that the one or two passenger trains booked to pass were replaced by busses with no more than half a dozen freight trains allowed due to the long sections and extended running time.

All points on the affected lines were secured for straight running before the switch-off and three inspectors appointed to man the three "block sections". Once everything was in place, the power was turned off so the whole panel went out, no track circuit or point indications or train descriptions. When a train arrived at our first signal, it would be dealt with in a similar manner to Absolute Block with the inspectors on the ground relaying instructions to the driver and informing us in the box when each train was entering or clear of the section, we recorded all the times, including entering section and train out of section in a train register just as would be done on AB.

Two things that particularly stick in the mind was the box supervisor writing the train headcode with a marker pen on a sheet of A4 paper and attaching it to the panel within the relevant section and looking out of the window and seeing a train that had been under our control for several miles with no trace of it other than a sheet of paper stuck on the panel.

Have more recently experienced a failure situation in a more compact area where the whole panel shut down with a similar effect as a power failure but in this case it was not possible to move a thing due to the complexity of the layout and moves required. It was quicker to wait for the S&T to turn up and replace three lots of equipment than muster enough people to pump and secure points to get things moving with verbal instructions.

 

[tygar2]

Now a Remote control (RC) failure where there is no communication between signal cantre and remote relay room which also cause all the outside signalling equipment to fail as well as giving you both TDM control & indications failure, will stop the job until a) the techs fix it, or b) you can find a small orange army of staff to start securing evething to move all the trapped trains.

The same goes if your local power your panel fails (panel is completely dead and dark) or your CBI such as smartlock fails as well (everything show red as well). Then its game over.

Can anyone expand on Option B? - After all points are secured, the location of all trains identified and lots on staff on hand - how is the movement of trapped trains managed? Does this have a name or is there a rule book module covering this?

Lots of temporary block working sections between trains perhaps?

 

[tygar2]

One particular event from around 25 years ago sticks in my mind though it was planned and not an emergency scenario.

The CEGB needed to do some work on the power suppy meaning that the power to the actual panel needed to be turned off although the domestic supply for things like the light and the kettle (most important!) was not affected. This affected some 24 1/2 miles of four track mainline, two of which would be under engineers possession albeit with no work sites within, and trains running along the remaining two which were to be split up into two block sections.

The time chosen was a Sunday night as that was the quietest night of the week, details are a bit hazy now but I seem to recollect that the one or two passenger trains booked to pass were replaced by busses with no more than half a dozen freight trains allowed due to the long sections and extended running time.

All points on the affected lines were secured for straight running before the switch-off and three inspectors appointed to man the three "block sections". Once everything was in place, the power was turned off so the whole panel went out, no track circuit or point indications or train descriptions. When a train arrived at our first signal, it would be dealt with in a similar manner to Absolute Block with the inspectors on the ground relaying instructions to the driver and informing us in the box when each train was entering or clear of the section, we recorded all the times, including entering section and train out of section in a train register just as would be done on AB.

Two things that particularly stick in the mind was the box supervisor writing the train headcode with a marker pen on a sheet of A4 paper and attaching it to the panel within the relevant section and looking out of the window and seeing a train that had been under our control for several miles with no trace of it other than a sheet of paper stuck on the panel.

Have more recently experienced a failure situation in a more compact area where the whole panel shut down with a similar effect as a power failure but in this case it was not possible to move a thing due to the complexity of the layout and moves required. It was quicker to wait for the S&T to turn up and replace three lots of equipment than muster enough people to pump and secure points to get things moving with verbal instructions.

Thanks for that. The last part really highlights how vulnerable the system is to unplanned shutdown/failure.

I'm not so sure these ROCs are a great idea. All seems a bit eggs in one basket...backed up with a prayer.

 

[Darbs]

Temporary block working can be used if it's practical to set up. Needs a lots of staff, much clamping of pints and level crossing attendants if required, but it can be done. I've been involved with it from out on the ground as a handsignalman and as a signaller, that's when you really earn your money when nothing is working properly or at all!

 

[tygar2]

Temporary block working can be used if it's practical to set up. Needs a lots of staff, much clamping of pints and level crossing attendants if required, but it can be done. I've been involved with it from out on the ground as a handsignalman and as a signaller, that's when you really earn your money when nothing is working properly or at all!

You probably can confirm this small detail - Can it be introduced without a signaller in the loop - eg. power failure, equipment failure or evacuation at signalbox?

Thanks

 

[Darbs]

Nothing can be down without the signaller. Even if we can't "see" where anything is. Contrail and ground staff are involved but it's still the signaller who issues any authority for a train to move.

 

[Sunset route]

Can anyone expand on Option B? - After all points are secured, the location of all trains identified and lots on staff on hand - how is the movement of trapped trains managed? Does this have a name or is there a rule book module covering this?

Lots of temporary block working sections between trains perhaps?

Option B doesn't really exist as you will never find enough staff to safely bring in any sort of degraded working involving multiple tracks ,multiple junctions over multiple panels/workstations.

In Temporary Block Working all points will have to be secured and left that way. Put it in simple terms, say the junction just north of Doncaster, you can either have York & the North or Leeds but not both. Now apply that logic to every junction that any large signalling control centre anywhere in the country and in the contexts of the original question and you will nothing will realistically move.

 

[LAX54]

Thanks for that. The last part really highlights how vulnerable the system is to unplanned shutdown/failure.

I'm not so sure these ROCs are a great idea. All seems a bit eggs in one basket...backed up with a prayer.

Which is what was said long before the first ROC was ever built !

A PSB / IECC yes, that controls a big area, but not like a ROC would, A PSB shutting would cause grief, but nowhere near the trouble a ROC would

 

[Bald Rick]

Which is what was said long before the first ROC was ever built !

A PSB / IECC yes, that controls a big area, but not like a ROC would, A PSB shutting would cause grief, but nowhere near the trouble a ROC would

Well it's 9 yards on Monday since the first purpose built ROC (the East Mids CC) opened. In that time, how many complete failures of all signalling has it had?

 

[Tomnick]

Well it's 9 yards on Monday since the first purpose built ROC (the East Mids CC) opened. In that time, how many complete failures of all signalling has it had?

...and how much less disruption would it have caused if Trent PSB fell over instead? The MML would be absolutely stuffed, and XC along the Derby - Sheffield corridor too. Not much better than the EMCC expiring (I'm only aware of one brief complete failure, which didn't cause many problems relatively - with numerous examples of more localised failures in the meantime, which have caused absolute chaos despite each only affecting a short portion of route).

 

[najaB]

Which is what was said long before the first ROC was ever built !

A PSB / IECC yes, that controls a big area, but not like a ROC would, A PSB shutting would cause grief, but nowhere near the trouble a ROC would

The fact that there are fewer ROCs than PSBs should mean that, while the impact of an outage is greater, the likelihood of that outage is lower (fewer buildings in which a fire could start, or where the power could be cut) and recovery of the system from an outage can start sooner (due to less travel time to the affected locations).

 

[carriageline]

Plus the ROCs have a lot more resilience, and stand by systems. Near enough everything is duplicated! The chance of a ROC falling over is a lot less likely compared to a PSB or mechanical boxb


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[LAX54]

MCS's have two systems, A and B, if one goes down, the other picks up instantly, however if it does not, then that w/stn will shut down, and signaller left with 5 or 6 blank screens. and looking at MCS w/stn failures on the logs, it does seem to happen
Problem is, the more complicated it gets, the more there is to trip it up !

 

[Sunset route]

MCS's have two systems, A and B, if one goes down, the other picks up instantly, however if it does not, then that w/stn will shut down, and signaller left with 5 or 6 blank screens. and looking at MCS w/stn failures on the logs, it does seem to happen
Problem is, the more complicated it gets, the more there is to trip it up !

We've got A & B circuits on both our route relay interlockings via dual TDMs as well as on our Smartlock CBIs.

 

[LAX54]

We've got A & B circuits on both our route relay interlockings via dual TDMs as well as on our Smartlock CBIs.

We have MCS and NX here, I am not sure our 'modern' MCS is as posh as yours, we too have an A & B for the MCS and an A & B for the TDM's but I think they are shared with the MCS's so just A&B.

The NX always seems much sturdier in its workings, seem to have far less 'failures' on the NX than we do the MCS

 

[carriageline]

Our MCS has been live 2 years now with no major hiccups (he's gone and done it now..)


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[Sunset route]

Our MCS has been live 2 years now with no major hiccups (he's gone and done it now..)


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Yeah thanks for wrecking my local train service pmsl

 

[Flying_Turtle]

Some people here clearly haven t ever heard about the extraordinary feats of railway Contractors, just armed with diggers, in screwing all sorts of redundancy!

 

[Flying_Turtle]

I can see the problem there, but that's not hard to mitigate against. Not all video systems continue to display the last valid frame.

i believe usually the feed has a clock interposed so you quickly realise something is not right

 

[Sunset route]

Some people here clearly haven t ever heard about the extraordinary feats of railway Contractors, just armed with diggers, in screwing all sorts of redundancy!

Sandhills (Merseyrail) IECC by any chance?

 

[superkev]

Very nearly happened at the EMCC. They had a power failure and the backup power supply also failed. They had around 30 minutes of battery power left, and started to bring trains to a stop in stations. Power was restored just before they lost power completely.

I surprised there isn't a plan B if one of the ROC 's failed or had to be evacuated for some reason. Unlikely but not impossible.
I've often wondered similarly about the air traffic control at west Drayton.
K