TPWS isolation question

[MrsCake21]

Hi all.

I have quite a specific couple of questions I need clarifying and answering please.

It's with regards to FULL isolation of the TPWS.
The older version and the newer version.

On the older version, when you fully isolated the TPWS with the key you also isolated the AWS!

On the newer version, is this the same?

I understand, on the newer version there is the option to Isolate the AWS on it's own. But not on the older version.

. I'm asking about the other way around. When you isolate the TPWS, does it isolate the AWS on the newer version just like it does on the older version.

Thanks

 

[Samsanbor]

Hi all.

I have quite a specific couple of questions I need clarifying and answering please.

It's with regards to FULL isolation of the TPWS.
The older version and the newer version.

On the older version, when you fully isolated the TPWS with the key you also isolated the AWS!

On the newer version, is this the same?

I understand, on the newer version there is the option to Isolate the AWS on it's own. But not on the older version.

. I'm asking about the other way around. When you isolate the TPWS, does it isolate the AWS on the newer version just like it does on the older version.

Thanks

I'm not entirely understanding your query regarding new/old version.

Full isolation of TPWS: TPWS and AWS are both isolated.

AWS isolated: TPWS working as per normal.

 

[Efini92]

Hi all.

I have quite a specific couple of questions I need clarifying and answering please.

It's with regards to FULL isolation of the TPWS.
The older version and the newer version.

On the older version, when you fully isolated the TPWS with the key you also isolated the AWS!

On the newer version, is this the same?

I understand, on the newer version there is the option to Isolate the AWS on it's own. But not on the older version.

. I'm asking about the other way around. When you isolate the TPWS, does it isolate the AWS on the newer version just like it does on the older version.

Thanks

What train are you referring to?
On the old trains isolating the aws would also isolate the tpws.

 

[Stigy]

Hi all.

I have quite a specific couple of questions I need clarifying and answering please.

It's with regards to FULL isolation of the TPWS.
The older version and the newer version.

On the older version, when you fully isolated the TPWS with the key you also isolated the AWS!

On the newer version, is this the same?

I understand, on the newer version there is the option to Isolate the AWS on it's own. But not on the older version.

. I'm asking about the other way around. When you isolate the TPWS, does it isolate the AWS on the newer version just like it does on the older version.

Thanks

The rules on isolating TPWS is the same old or new as far as I’m aware. The new system just has extra functionality which tells you when you’ve had a SPAD? The system operates the same, no matter which version. Unless I’m misunderstanding the old/new thing.

 

[driverd]

The rules on isolating TPWS is the same old or new as far as I’m aware. The new system just has extra functionality which tells you when you’ve had a SPAD? The system operates the same, no matter which version. Unless I’m misunderstanding the old/new thing.

It might be traction specific.

Because TPWS was back worked into the AWS, isolation of the TPWS is only achieved by isolating the AWS (thus taking out the TPWS also), confusingly, on most sprinters (for example) this is flaged as TPWS isolation. On older locos, this is achieved by AWS isolation.

On newer stock, the two systems exist separately and can be isolated separately. Eg: isolating AWS would not remove TPWS or vice versa. The version of TPWS in use doesn't matter, its more about how the systems are wired in.

 

[MrsCake21]

It might be traction specific.

Because TPWS was back worked into the AWS, isolation of the TPWS is only achieved by isolating the AWS (thus taking out the TPWS also), confusingly, on most sprinters (for example) this is flaged as TPWS isolation. On older locos, this is achieved by AWS isolation.

On newer stock, the two systems exist separately and can be isolated separately. Eg: isolating AWS would not remove TPWS or vice versa. The version of TPWS in use doesn't matter, its more about how the systems are wired in.

Hi. This is where my confusion lies.

Temporary isolation is different from FULL isolation.

You're correct that on the older system, (irrelevant of traction), Full isolation of either system is just one switch. You enter your train key and that's it, both tpws and aws are Fully isolated. Temp isolation however, each is separate.
I'm only referring to FULL isolation.

The new system, (irrelevant of traction), there is a separate, Full isolation AWS only switch. (i't next to the TEMP tpws switch) so, you can FULL isolate the AWS and not the TPWS.
My question however, is the other way around. When FULL isolation of the TPWS, does this still isolate the AWS. (like the older version it does)


The newer version has more lights, alerts, and extra brake release step, (pressing 2 buttons at once) and the option of separate AWS Full isolation switch.

I think the answer to my question is yes. The FULL isolation of the tpws STILL isolates the AWS...

I'm not 100%

 

[Horizon22]

I think the answer to my question is yes. The FULL isolation of the tpws STILL isolates the AWS...

I'm not 100%

On stock I am aware of which tends to be newer, this is true.

 

[NSEWonderer]

On 701s for example, you can full isolate the AWS independently and It won't affect the TPWS system. However if you full isolate the TPWS system then it will take out the AWS aswell.
Desiro's its also the same, separate AWS full isolation switch that once set can only be reset by fitter, doesn't again affect TPWS. But the TPWS full isolation switch when isolated like previous will require a fitter to reset aswell as also knocks out the AWS system.

In short both the 701 and Desiros:

Full AWS Isolation = AWS: Isolated, TPWS: Not Affected/Isolated
Full TPWS Isolation = TPWS + AWS: Isolated

 

[Stigy]

Hi. This is where my confusion lies.

Temporary isolation is different from FULL isolation.

You're correct that on the older system, (irrelevant of traction), Full isolation of either system is just one switch. You enter your train key and that's it, both tpws and aws are Fully isolated. Temp isolation however, each is separate.
I'm only referring to FULL isolation.

The new system, (irrelevant of traction), there is a separate, Full isolation AWS only switch. (i't next to the TEMP tpws switch) so, you can FULL isolate the AWS and not the TPWS.
My question however, is the other way around. When FULL isolation of the TPWS, does this still isolate the AWS. (like the older version it does)


The newer version has more lights, alerts, and extra brake release step, (pressing 2 buttons at once) and the option of separate AWS Full isolation switch.

I think the answer to my question is yes. The FULL isolation of the tpws STILL isolates the AWS...

I'm not 100%

Temporary isolation is different to full isolation anyway, in all circumstances and traction types.

 

[driverd]

The new system, (irrelevant of traction), there is a separate, Full isolation AWS only switch. (i't next to the TEMP tpws switch) so, you can FULL isolate the AWS and not the TPWS.
My question however, is the other way around. When FULL isolation of the TPWS, does this still isolate the AWS. (like the older version it does)

Not always true, on some older locos with TPWS 4 modified in, the only way to full isolate is via the AWS isolation.

I think the answer to my question is yes. The FULL isolation of the tpws STILL isolates the AWS...

I'm not 100%

I'm not 100%, maybe someone can correct me as it's a while ago now, but I think the CAF Civities can isolate them independently.

 

[driver9000]

I'm not 100%, maybe someone can correct me as it's a while ago now, but I think the CAF Civities can isolate them independently.

Correct.

 

[357]

It's traction specific and you're sweeping statements can't be considered the case for all fleets/types in operation on the network.

Every traction I've ever signed has had its own quirks regarding AWS/TPWS isolation.

 

[Efini92]

Hi. This is where my confusion lies.

Temporary isolation is different from FULL isolation.

You're correct that on the older system, (irrelevant of traction), Full isolation of either system is just one switch. You enter your train key and that's it, both tpws and aws are Fully isolated. Temp isolation however, each is separate.
I'm only referring to FULL isolation.

The new system, (irrelevant of traction), there is a separate, Full isolation AWS only switch. (i't next to the TEMP tpws switch) so, you can FULL isolate the AWS and not the TPWS.
My question however, is the other way around. When FULL isolation of the TPWS, does this still isolate the AWS. (like the older version it does)


The newer version has more lights, alerts, and extra brake release step, (pressing 2 buttons at once) and the option of separate AWS Full isolation switch.

I think the answer to my question is yes. The FULL isolation of the tpws STILL isolates the AWS...

I'm not 100%

No I don’t think you’re correct in that statement.
If you only have one isolation switch and it’s labelled tpws, but it also isolates the aws. Then it’s labelled up wrong. It should be the aws isolation.
If you have separate aws and tpws isolation switches, the tpws being isolated will not isolate the aws. If it does, it’s been wired up wrong.

 

[NSEWonderer]

No I don’t think you’re correct in that statement.
If you only have one isolation switch and it’s labelled tpws, but it also isolates the aws. Then it’s labelled up wrong. It should be the aws isolation.
If you have separate aws and tpws isolation switches, the tpws being isolated will not isolate the aws. If it does, it’s been wired up wrong.

Its Train Stock dependant, but definitely on the stock i drive it is the case as I've put in post #8 and that was by design rather than wrong wiring.

 

[Efini92]

Its Train Stock dependant, but definitely on the stock i drive it is the case as I've put in post #8 and that was by design rather than wrong wiring.

Sorry I was referring to old stock manufactured before tpws was introduced.
Though that is rather bizarre that the tpws takes out the aws on the 701’s, what’s the reason for that?

 

[NSEWonderer]

Sorry I was referring to old stock manufactured before tpws was introduced.
Though that is rather bizarre that the tpws takes out the aws on the 701’s, what’s the reason for that?

Rulebook standards: RIS-0775-CCS Iss 3
AWS and TPWS Application Requirements

G 5.3.9.4 This control provides a means of completely isolating the AWS and TPWS
functionality on the rail vehicle so that it can be moved.

 

[D365]

It's traction specific and you're sweeping statements can't be considered the case for all fleets/types in operation on the network.

Every traction I've ever signed has had its own quirks regarding AWS/TPWS isolation.

These quirks shouldn’t exist in rolling stock from the last ~10 years, which should be designed in accordance with RIS-0775-CCS.

However @Nym and I know that compliance with Group Standards seems to be all too difficult…

 

[Nym]

These queiks shouldn’t exist in rolling stock from the last ~10 years, which should be designed in accordance with RIS-0775-CCS.

However @Nym and I know that compliance with Group Standards seems to be all too difficult…

Indeed…
The confusing arising in the nomenclature of isolation controls for AWS, TPS and as a complete TPWS lies entirely at the door of the RSSB for their definition of terms regarding “Isolation” and allowing the sub system designers, and those of more contemporary systems to use the word “Isolate” incorrectly for a number of years now.
“Back in My Day” or “On my old fleets” isolate meant isolate, where in the world of RSSB, Unipart and Thales, it can be used to mean a very different thing.

To go back up to the OP's question,

Do what your traction course tells you!
Even if we know it's wrong, you can't be hauled up in front of the bloke with the curly wig for doing what's in your traction course.


And now to those pulling the contempoary standards.

TPWS has been through at least three standards and up to four iterations of each of these. With RIS-0775-CCS Issue 3 being the 4th iteration of a standard that relates to Enhanced TPWS with it's distinctions of trip type (OSS vs SPAD), extra buttons and timers, and voice annunciators that are actually wrong and talk over other cab warnings when starting up modern traction. Each of these standards will have had a slightly different way of naming things.

 

[driverd]

Rulebook standards: RIS-0775-CCS Iss 3
AWS and TPWS Application Requirements

View attachment 183260View attachment 183264

I also think it could be argued an interpretation of this standard would be to have two switches, as nowhere does it state that it must be an AWS & TPWS isolation switch. It would seem a reasonable interpretation (that appears to have been taken on board by atleast one manufacture) that the / between AWS and TPWS simply means the standard applies to both systems and the switches can be 2 separate ones.

 

[NSEWonderer]

I also think it could be argued an interpretation of this standard would be to have two switches, as nowhere does it state that it must be an AWS & TPWS isolation switch. It would seem a reasonable interpretation (that appears to have been taken on board by atleast one manufacture) that the / between AWS and TPWS simply means the standard applies to both systems and the switches can be 2 separate ones.

The bit I quoted doesn't say "or" it says and. It also talks of the switch as one. There is a seperate section above the AWS / TPWS isolation control that talks about the separate AWS switch and its specification. But as mentioned I've only quoted the standard in reference to why its been done as so on the Desiro and 701.

 

[driverd]

The bit I quoted doesn't say "or" it says and. It also talks of the switch as one. The standard above it the talks about the separate AWS switch and its specification

The wording in the standard itself, rather than the heading, however, has it as a /, not &. So, I can only presume that's the interpretation taken on by manufactures who fit independent isolations (eg:CAF)?

 

[NSEWonderer]

The wording in the standard itself, rather than the heading, however, has it as a /, not &. So, I can only presume that's the interpretation taken on by manufactures who fit independent isolations (eg:CAF)?

That could be how caf interpreted it. But at least where im from the standard was followed as a seperate AWS isolation switch and then a AWS & TPWS isolation switch(May be labelled as Full TPWS isolation switch in some stock, does the same thing of knocking the AWS if they've interpreted the standard as in the case of 701 and Desiro).

Maybe the standard is open to some interpretation agreed but from what im seeing, new stock seem to be closing in on one direction. The Aventra family unless anyone knows(one not to) use the same setup as the 701s in this respect.

 

[D365]

When TPWS was first fitted, 20-something years ago, the existing AWS Isolation switch became an AWS & TPWS Isolation switch, but wasn’t always relabelled as such. This was very much the start of the confusion…

 

[NSEWonderer]

When TPWS was first fitted, 20-something years ago, the existing AWS Isolation switch became an AWS & TPWS Isolation switch, but wasn’t always relabelled as such. This was very much the start of the confusion…

Yeah the 458s are as so, labeled as Train Protection & Warning system Isolation originally were just AWS I heard.

It does make sense that newer trains have one aws isolation and then a TPWS isolation switch(which isolates both). If you isolate TPWS then logically you're isolating the warning system which is the AWS. If we just wanted to isolate the train protection bit of TPWS then it would only have been known as TP Isolation(Train Protection Isolation), which rather just makes things additionally confusing. It does seem this part if the standard has been somewhat consistent even if the labeling naming wise hasn't?

 

[357]

When TPWS was first fitted, 20-something years ago, the existing AWS Isolation switch became an AWS & TPWS Isolation switch, but wasn’t always relabelled as such. This was very much the start of the confusion…

I've driven trains fitted with TPWS from new that still have them both on one switch labeled AWS.

 

[D365]

I've driven trains fitted with TPWS from new that still have them both on one switch labeled AWS.

And this is how the initial confusion was further propagated…

It does make sense that newer trains have one aws isolation and then a TPWS isolation switch(which isolates both). If you isolate TPWS then logically you're isolating the warning system which is the AWS. If we just wanted to isolate the train protection bit of TPWS then it would only have been known as TP Isolation(Train Protection Isolation), which rather just makes things additionally confusing.

On vehicles with Enhanced TPWS, the TPWS only isolation is designated as ”TPWS Temporary Isolation”.

 

[NSEWonderer]

And this is how the initial confusion was further propagated…


On vehicles with Enhanced TPWS, the TPWS only isolation is designated as ”TPWS Temporary Isolation”.

Ah just realised, yes that is true.