Operational procedure when on-train AWS is isolated?

[martin2345uk]

Getting various different answers from people I ask this to so throwing it out to a wider audience

TW5 Section 4.5 says that if the AWS is defective, has been isolated, or the seal is broken on the isolating switch, a train is restricted to 50/60mph unless a competent person is present.

So if you relieve a train and the seal is missing on the handle but the AWS is not isolated and is working fine, this reads to me as you’re still restricted to those lower speeds… yes..? No..?

 

[Nippy]

Yup, reads the same to me. the seal has been broken for a reason.

 

[skyhigh]

So if you relieve a train and the seal is missing on the handle but the AWS is not isolated and is working fine, this reads to me as you’re still restricted to those lower speeds… yes..?

My reading of that is yes, you are limited to the lower speed (though I don't sign any traction where there is a specific AWS isolation with a seal.)

 

[Tynwald]

Contact your relevant maintenance control, who will instruct you what to do.

 

[martin2345uk]

Do control have the power to overrule the rulebook? (Genuine question)

 

[skyhigh]

Do control have the power to overrule the rulebook? (Genuine question)

Generally no. However... company instructions may be more restrictive than the rule book (which I suppose may be seen as overruling it) and there are sometimes different interpretations of what certain parts of the rule book says!

 

[philthetube]

Interesting, defective tripcock on the underground, the train does not move without a second person in the cab, except in very limited circumstances, and trains are speed controlled and will only do 10mph, no override available.

 

[DownFast]

Generally no. However... company instructions may be more restrictive than the rule book (which I suppose may be seen as overruling it) and there are sometimes different interpretations of what certain parts of the rule book says!

Company instructions can be less restrictive than the Rule Book if a deviation is applied for and granted by RSSB.

For example, section 3.4 of SS1 states that:
'You must give the ‘ready-to-start’ signal to the driver by using the bell or buzzer communication. If there is no bell or buzzer communication, you must give the ‘ready-to-start’ signal to the driver by displaying a green handsignal'.

On 80x, you can't give a green handsignal as there are no droplight windows, and all doors are on the interlock circuit which means that the guard can't check that the orange bodyside hazard lights are extinguished. So GWR have applied for and been granted a deviation from SS1 which allows the guard to use the cab-to-cab to give the driver a verbal 'ready-to-start' instead of a green handsignal.

 

[skyhigh]

Company instructions can be less restrictive than the Rule Book if a deviation is applied for and granted by RSSB.

For example, section 3.4 of SS1 states that:
'You must give the ‘ready-to-start’ signal to the driver by using the bell or buzzer communication. If there is no bell or buzzer communication, you must give the ‘ready-to-start’ signal to the driver by displaying a green handsignal'.

On 80x, you can't give a green handsignal as there are no droplight windows, and all doors are on the interlock circuit which means that the guard can't check that the orange bodyside hazard lights are extinguished. So GWR have applied for and been granted a deviation from SS1 which allows the guard to use the cab-to-cab to give the driver a verbal 'ready-to-start' instead of a green handsignal.

That's a fair point. I thought of a less restrictive company instruction not long after I posted that!

 

[LowLevel]

Company instructions can be less restrictive than the Rule Book if a deviation is applied for and granted by RSSB.

For example, section 3.4 of SS1 states that:
'You must give the ‘ready-to-start’ signal to the driver by using the bell or buzzer communication. If there is no bell or buzzer communication, you must give the ‘ready-to-start’ signal to the driver by displaying a green handsignal'.

On 80x, you can't give a green handsignal as there are no droplight windows, and all doors are on the interlock circuit which means that the guard can't check that the orange bodyside hazard lights are extinguished. So GWR have applied for and been granted a deviation from SS1 which allows the guard to use the cab-to-cab to give the driver a verbal 'ready-to-start' instead of a green handsignal.

Really? That seems a bit bizarre given that situation has existed for years on all sorts of rolling stock and the solution has always been to give the driver the green flag before closing the local door regardless of what the bodyside lights are doing because you can't check the bodyside light has extinguished on your own vehicle before shutting the local door anyway - because it never will.

That includes for example GWR's own 158s where the orange light will never be seen to be extinguished on the carriage with the guard's local door before they shut it and give the ready to start signal.

What makes dispatching an 80x with a green flag different from dispatching an 80x from anything other the cab door, given you can't see the hazard lights anyway then either?

That seems very odd to me.

 

[Taunton]

Did the AWS rule get added or changed after the 1997 Southall accident (125mph with no AWS)?

The accident report says the procedure then was that in this event the driver was to report AWS failure to "the signalman". Quite what reporting this to the Swansea High Street signalbox, at the start of the journey, was to achieve is not apparent, nor that it would be in any way communicated to every signalman along the way, including the panel signalman at Slough several hours later, who decided to pull the train up for a conflicting movement.

 

[O L Leigh]

Getting various different answers from people I ask this to so throwing it out to a wider audience

TW5 Section 4.5 says that if the AWS is defective, has been isolated, or the seal is broken on the isolating switch, a train is restricted to 50/60mph unless a competent person is present.

So if you relieve a train and the seal is missing on the handle but the AWS is not isolated and is working fine, this reads to me as you’re still restricted to those lower speeds… yes..? No..?

Your reading of the rules certainly seems correct. A missing seal on the isolation switch would count as defective AWS and therefore subject to the same restrictions. If it were me and the driver I relieved fails to mention it on the handover, I would report it myself to Control and apply the rule book instructions.

As to what happens next, the rules say you are to follow the instructions you receive. I presume that this is not prescriptive because it’s likely to depend on the precise circumstances of the failure. Quite what those might be would presumably be down to Control’s procedures. However, I would guess that it would be to “tip out” and go empty somewhere the train can be dealt with.

Did the AWS rule get added or changed after the 1997 Southall accident (125mph with no AWS)?

The accident report says the procedure then was that in this event the driver was to report AWS failure to "the signalman". Quite what reporting this to the Swansea High Street signalbox, at the start of the journey, was to achieve is not apparent, nor that it would be in any way communicated to every signalman along the way, including the panel signalman at Slough several hours later, who decided to pull the train up for a conflicting movement.

Yes they did. You may no longer start a journey with defective or isolated AWS.

I’m not sure that informing the signaller would have guaranteed a clear run, but I’m sure that doing so would result in the train being regulated with a bit more caution than might otherwise have been the case.

 

[Taunton]

There must have been an earlier rule change the other way, for back in steam days and early diesels no loco was allowed on GWR/Western Region main line work without the ATC working. This was the main reason why locos from other regions were changed at the boundary. It must have been given up in the late 1960s when diesels from other regions started to work through onto the WR. Inevitably within a few years there was a serious accident, at Bridgwater, when an LMR Peak with only BR AWS, not the WR ATC, ran through signals at speed into the train standing ahead.

 

[Estrella709]

One thing that throws a spanner in the works with this is that with the older AWS/TPWS systems , isolating the AWS also isolates the TPWS. So on any traction with the older installation, once the AWS (and therefore TPWS as well) is isolated, the train cannot move until a competent person is provided and only then at max 40mph.
With the newer AWS/TPWS system you can isolate the AWS/TPWS together as the old type or each system seperately leaving the other operational in which case the rules then allow the train to proceed at reduced speed without a competent person.
Thats my understanding anyway.

 

[martin2345uk]

One thing that throws a spanner in the works with this is that with the older AWS/TPWS systems , isolating the AWS also isolates the TPWS. So on any traction with the older installation, once the AWS (and therefore TPWS as well) is isolated, the train cannot move until a competent person is provided and only then at max 40mph.
With the newer AWS/TPWS system you can isolate the AWS/TPWS together as the old type or each system seperately leaving the other operational in which case the rules then allow the train to proceed at reduced speed without a competent person.
Thats my understanding anyway.

That's interesting.. where does it say that if both are isolated you cannot move at all without a competent person? I can see the sections for each of them separately but can't seem to see the combined part!

 

[Efini92]

One thing that throws a spanner in the works with this is that with the older AWS/TPWS systems , isolating the AWS also isolates the TPWS. So on any traction with the older installation, once the AWS (and therefore TPWS as well) is isolated, the train cannot move until a competent person is provided and only then at max 40mph.
With the newer AWS/TPWS system you can isolate the AWS/TPWS together as the old type or each system seperately leaving the other operational in which case the rules then allow the train to proceed at reduced speed without a competent person.
Thats my understanding anyway.

That’s only if the DSD is isolated as well.

== Doublepost prevention - post automatically merged: 30 Mar 2022 ==

Getting various different answers from people I ask this to so throwing it out to a wider audience

TW5 Section 4.5 says that if the AWS is defective, has been isolated, or the seal is broken on the isolating switch, a train is restricted to 50/60mph unless a competent person is present.

So if you relieve a train and the seal is missing on the handle but the AWS is not isolated and is working fine, this reads to me as you’re still restricted to those lower speeds… yes..? No..?

View attachment 112211

It says it’s 60 mph. You’re best off speaking to your control as the may have some sort of derogation in their contingency plan.

 

[Indistinct]

Are we talking about a 66 here? From memory the AWS isolation switch is in the mcb cabinet in Cab 1 so not the sort of thing you’d check when relieving?

 

[martin2345uk]

Are we talking about a 66 here? From memory the AWS isolation switch is in the mcb cabinet in Cab 1 so not the sort of thing you’d check when relieving?

We are indeed and no it's not, in this example it was mentioned as part of handover.

 

[Eccles1983]

One thing that throws a spanner in the works with this is that with the older AWS/TPWS systems , isolating the AWS also isolates the TPWS. So on any traction with the older installation, once the AWS (and therefore TPWS as well) is isolated, the train cannot move until a competent person is provided and only then at max 40mph.
With the newer AWS/TPWS system you can isolate the AWS/TPWS together as the old type or each system seperately leaving the other operational in which case the rules then allow the train to proceed at reduced speed without a competent person.
Thats my understanding anyway.

They are treated as one and the same for degraded working.

So no need for a competent person put max speed of 60mph.

As mentioned you cannot move the train if aws/tpws AND the dsd/dvd have been isolated. Once a person has been found then they take the place of one of the isolated systems - max speed 60mph.

 

[2192]

They are treated as one and the same for degraded working.

So no need for a competent person put max speed of 60mph.

As mentioned you cannot move the train if aws/tpws AND the dsd/dvd have been isolated. Once a person has been found then they take the place of one of the isolated systems - max speed 60mph.

What are the qualifications required of such a "competent person"?

 

[skyhigh]

What are the qualifications required of such a "competent person"?

At my TOC at least it depends on the fault.

TPWS/AWS it has to be someone with driver competency.
DSD/Vigilance it can be the guard as they just need to check the driver is still alive, basically.

 

[Efini92]

What are the qualifications required of such a "competent person"?

For aws it has to be someone who’s a qualified driver and has the appropriate route knowledge.

 

[E27007]

Qualified driver with route knowledge, and a "call and respond " dialogue between the two, they are both observing signals and speed limits (AWS magnets are for more than signals).
Journey should also be to the closest depot / workshop where the AWS system can be repaired, or even take the cab out of use, a reversal so the other cab is used (hopefully not affected,) or box the faulty cab in, couple two 4-car units together and drive from the leading functional cab.

 

[pitdiver]

Interesting, defective tripcock on the underground, the train does not move without a second person in the cab, except in very limited circumstances, and trains are speed controlled and will only do 10mph, no override available.

I as a station supervisor with operational training carried out that duty on a few occasions.

 

[niggill617@gma]

what if the se

Yup, reads the same to me. the seal has been broken for a reason.

What if the seal is the red plastic strand type fitted in slipshod fashion, too long and slack, enabling isolation. I had this and the controller said log and continue. So I did.