5 conditions to pass 2 reds at danger with authority.

[Ditop23]

Hi all. A little confused on a couple of these conditions.

1)
1 of the conditions is, that the 2nd signal does not have TPWS installed.
Why is this please? Why does it matter. Why only the 2nd signal?

2)
Another condition is, there can not be a distant signal between the 2. Why is this please?

3)
Separate to the conditions, What does it mean if there are 3 signals at fault in a row? Is this where it becomes ESW or TBW?

Thanks all

 

[Juliet Barvo]

If there were three consecutive reds which the signaler would have to authorise you to pass at Danger, they would most likely treat each one individually: they would authorise you to pass the first, then when you got to the second they would authorise you to pass that at danger, and again at the third.
ESW being the new cheaper TBW would probably only be introduced for something bigger as there are forms that have to be dictated which take time and risks associated with ESW that are not present for authorising people to pass single signals at danger.

== Doublepost prevention - post automatically merged: 28 Jun 2025 ==

Hi all. A little confused on a couple of these conditions.

1)
1 of the conditions is, that the 2nd signal does not have TPWS installed.
Why is this please? Why does it matter. Why only the 2nd signal?

2)
Another condition is, there can not be a distant signal between the 2. Why is this please?

3)
Separate to the conditions, What does it mean if there are 3 signals at fault in a row? Is this where it becomes ESW or TBW?

Thanks all

1. When you pass a Single Red Signal with Authority, you use Train Stop Overide, which disables the TPWS for 20seconds on a Passenger train (60 seconds on a freight train). If the second signal was fitted with TPWS then the TSO button would have to be pressed at the second signal without further discussion with the signaller: the RSSB probably don't want Drivers getting in the habit of pressing TSO on the move without reference to the signaller as it's ripe for abuse.

2. There cannot be a distant signal between the two consecutive Reds to be passed at Danger. Who knows why this is a condition. WIth this rule baing relatively new, after a successful period of operation, maybe they will loosen the scope and allow this

 

[CC 72100]

1. If the second signal was fitted with TPWS then the TSO button would have to be pressed at the second signal without further discussion with the signaller: the RSSB probably don't want Drivers getting in the habit of pressing TSO on the move without reference to the signaller as it's ripe for abuse.

Its also fair to say that either forgetting or mistiming the use of the TSO button is a big enough issue when being authorised to pass a signal at danger from stationary, a risk which would only be more likely when travelling towards the second signal at danger when trying to judge when to press the button on the move.

Additionally this second Signal could also be fitted with TPWS OSS grids which could be activated if they have a low-ish trip speed but one that is below the 50mph maximum speed for the movement.

 

[Ditop23]

Thanks

Could you not just temporary isolate the tpws for the duration?

 

[CC 72100]

Thanks

Could you not just temporary isolate the tpws for the duration?

Yes from a practical "could you do it" perspective, no from a "does the rule book allow it" perspective.

Also when passing two consecutive signals at danger a pre-condition is that signal 3 (the first one working properly and to be obeyed) has to be displayed a Proceed aspect, so when is the natural opportunity to re-instate the TPWS? - There isn't.

In other forms of degraded working there are natural opportunities to reinstate the TPWS at the exit/end point of the degraded working.

== Doublepost prevention - post automatically merged: 28 Jun 2025 ==

2)
Another condition is, there can not be a distant signal between the 2. Why is this please?

My guess is there is a risk that if a driver is just physically counting signals, they confuse the distant signal with being signal 2 to be ignored?

Its obvious when signals are plated as UM123, then UM125R, them UM125 - I'm told very obviously that UM125R is a Distant signal, and is the Distant for UM125.

However re-sigalling schemes these days tend to give each signal - Distant or Stop - a distinct number, so when given a list of signals, say DF1224, DF1226 and DF1228 it isn't obvious that DF1226 is the Distant for DF1228. After all, drivers need to know where the signals are, not their numbers.

 

[Juliet Barvo]

Thanks

Could you not just temporary isolate the tpws for the duration?

That would be ESW

 

[BrummieBobby]

The number of conditions on the "passing two at danger" rule means that there are few chances to use it when dealing with an ongoing failure.

I had a fairly heated disagreement with a controller about this rule when dealing with a track circuit failure going into a yard; the track circuit in question was in the overlap of the first signal (holding it at danger) and housed the second signal, which protected the entrance to a yard (holding it at danger) however beyond the last track circuit was a stop board, which the PIC would authorise movements to pass via a conversation with the signaller.

Said controller tried to argue that following PIC approval of a move, the stop board was technically showing a proceed; I refused this explanation, saying that it was a stop and telephone board and, by default, it was incapable of showing a proceed aspect.

 

[Juliet Barvo]

Said controller tried to argue that following PIC approval of a move, the stop board was technically showing a proceed; I refused this explanation, saying that it was a stop and telephone board and, by default, it was incapable of showing a proceed aspect.

"the stop board was technically showing a proceed" is a quality bit of spin. "Well yes, that Stop board says 'contact shunter for instructions' and I've already Instructed them to proceed, so it's a proceed aspect". Reasoning that Sir Humphrey would be proud of.

 

[godfreycomplex]

Said controller tried to argue that following PIC approval of a move, the stop board was technically showing a proceed

As a former NR controller my sober, professional response to this is “is it ****”

There’s a big red circle on stop boards for a reason eh

== Doublepost prevention - post automatically merged: 28 Jun 2025 ==

2. There cannot be a distant signal between the two consecutive Reds to be passed at Danger. Who knows why this is a condition.

There was a reason but I can’t for the life of me remember the exact wording I’m afraid. Something to do (and I’m not saying this is entirely logical) with there being an increased SPAD risk with the exit signal (the third signal, if you like), if that were to be at danger, compared to 3 or 4 aspect.

 

[PudseyBearHST]

As a former NR controller my sober, professional response to this is “is it ****”

There’s a big red circle on stop boards for a reason eh

== Doublepost prevention - post automatically merged: 28 Jun 2025 ==


There was a reason but I can’t for the life of me remember the exact wording I’m afraid. Something to do (and I’m not saying this is entirely logical) with there being an increased SPAD risk with the exit signal (the third signal, if you like), if that were to be at danger, compared to 3 or 4 aspect.

Could it be to do with AWS on distant giving a bell instead of horn (as the signal it pertains to is faulty) hence clearing the AWS sunflower to black?

 

[godfreycomplex]

Could it be to do with AWS on distant giving a bell instead of horn (as the signal it pertains to is faulty) hence clearing the AWS sunflower to black?

Yes that could be part of it actually

 

[Tomnick]

Could it be to do with AWS on distant giving a bell instead of horn (as the signal it pertains to is faulty) hence clearing the AWS sunflower to black?

Not unless there's another (wrong side) fault present, for which the driver should be advised separately anyway.

My best guess is that the requirement for there to be no intervening distant signal is a crude tool to limit the distance between the two stop signals being passed in the same authority, so that you're not passing the second at danger many miles (and minutes) since the authority was actually received.

 

[Samsanbor]

2)
Another condition is, there can not be a distant signal between the 2. Why is this please?


The signaller can authorise a driver to pass TWO CONSECUTIVE MAIN LINE STOP SIGNAL AT DANGER when there is no DISTANT SIGNAL between the TWO MAIN ASPECTS (plus the other requirements already mentioned).

The reason of this is because if a distant signal intervenes between the two main stop signals then it will make a different scenario, the rule book requirement is "TWO CONSECUTIVE" MAIN LINE STOP SIGNAL AT DANGER, distant signal is not a stop signal.

For other scenarios then Emergency Special Working or Temporary Block Working may be required instead.

 

[Annetts key]

Wasn’t this rule introduced to speed up things when ONE failure affected TWO consecutive section (stop) signals? For example a fault affecting the overlap of a controlled signal will hold both the protecting signal and the signal in rear at red. Before the introduction of this rule the signaller would have had to authorise the driver past each signal separately, with the train stopping both times.

 

[Ditop23]

If there were three consecutive reds which the signaler would have to authorise you to pass at Danger, they would most likely treat each one individually: they would authorise you to pass the first, then when you got to the second they would authorise you to pass that at danger, and again at the third.
ESW being the new cheaper TBW would probably only be introduced for something bigger as there are forms that have to be dictated which take time and risks associated with ESW that are not present for authorising people to pass single signals at danger.

== Doublepost prevention - post automatically merged: 28 Jun 2025 ==



1. When you pass a Single Red Signal with Authority, you use Train Stop Overide, which disables the TPWS for 20seconds on a Passenger train (60 seconds on a freight train). If the second signal was fitted with TPWS then the TSO button would have to be pressed at the second signal without further discussion with the signaller: the RSSB probably don't want Drivers getting in the habit of pressing TSO on the move without reference to the signaller as it's ripe for abuse.

2. There cannot be a distant signal between the two consecutive Reds to be passed at Danger. Who knows why this is a condition. WIth this rule baing relatively new, after a successful period of operation, maybe they will loosen the scope and allow this

Thanks for all the replies...

So I'm guessing if all 5 conditions are NOT met, they will be dealt with as separate single signals to pass at danger.

For example, If 2 main signals were faulty BUT there was tpws on the 2nd. Then you would only be told about each one separately as you arrived at each signal and then phoned the signaller?

Thanks

 

[Supercoss]

Work is underway to change ( challenge ) rule book clause in S5 part 7
from
”The 2nd main aspect stop signal is not fitted with TPWS”
to
” The 2nd main aspect stop signal is not fitted with working TPWS”
so in long duration incidents the signal technician can disconnect TPWS OSS and TSS allowing a train to pass 2 signals at danger.

this removes the issue of being tripped at 50 mph on TPWS equipment for second signal

 

[godfreycomplex]

Work is underway to change ( challenge ) rule book clause in S5 part 7
from
”The 2nd main aspect stop signal is not fitted with TPWS”
to
” The 2nd main aspect stop signal is not fitted with working TPWS”
so in long duration incidents the signal technician can disconnect TPWS OSS and TSS allowing a train to pass 2 signals at danger.

this removes the issue of being tripped at 50 mph on TPWS equipment for second signal

Hmmmm, not entirely overjoyed about the prospect of full on disconnecting a class A safety system for no other reason than to avoid a couple of minutes of delay

 

[Annetts key]

Work is underway to change ( challenge ) rule book clause in S5 part 7
from
”The 2nd main aspect stop signal is not fitted with TPWS”
to
” The 2nd main aspect stop signal is not fitted with working TPWS”
so in long duration incidents the signal technician can disconnect TPWS OSS and TSS allowing a train to pass 2 signals at danger.

this removes the issue of being tripped at 50 mph on TPWS equipment for second signal

Not knocking you, but this idea that the S&T will be able to disconnect a TPWS while there is a failure that is causing two signals to be held at red, and therefore is a high priority failure that requires S&T attendance, is ignoring the practical problem that with the limited number of S&T staff, it's unlikely that there will be anyone available to carry out the disconnection.

Okay, there may be the occasional failure where fixing the problem cannot be progressed (maybe waiting for replacement parts, or some other reason) but this is likely to be exception.

I've had plenty of discussions about what is the higher priority with other "can you disconnect" or "can you fix the signal at red" requests. And most of the time when faced with the reality, the powers that be, decided that they wanted the priority to be trying to fix the fault.

 

[westcoaster]

If there were three consecutive reds which the signaler would have to authorise you to pass at Danger, they would most likely treat each one individually: they would authorise you to pass the first, then when you got to the second they would authorise you to pass that at danger, and again at the third.
ESW being the new cheaper TBW would probably only be introduced for something bigger as there are forms that have to be dictated which take time and risks associated with ESW that are not present for authorising people to pass single signals at danger.

== Doublepost prevention - post automatically merged: 28 Jun 2025 ==





2. There cannot be a distant signal between the two consecutive Reds to be passed at Danger. Who knows why this is a condition. WIth this rule baing relatively new, after a successful period of operation, maybe they will loosen the scope and allow this

2. The simple answer is the distant is showing a proceed aspect, so in actulal facrt you'd be passing aspect 1&3 at danger.