Yellow Ends...

[Gandalf]

Foggy,
The Tornado site does give a list of what they are having to install on a new loco but they have an exemption on the yellow bits. I seem to remember radio is in as is most of what you mentioned butthe old AWS is out.
The story of the creating of this new loco is worth reading if you have an hour or so to spare.
John (G)

[Foghut]

Originally Posted by Gandalf

Foggy,
The Tornado site does give a list of what they are having to install on a new loco but they have an exemption on the yellow bits. I seem to remember radio is in as is most of what you mentioned butthe old AWS is out.

Thanks for that John. I think that either the author is mistaken or the description is somewhat misleading. It says....

" By the time Tornado is in service, the new TPWS (Train Protection and Warning System) will be required. This is designed to be a direct replacement for the AWS as fitted to air braked diesel and electric stock...

The way I read this is that it's suggesting that a new TPWS installation replaces AWS. If so then it's misinformed. AWS is still very much a respected Safety System. In fact TPWS is integrated with AWS on modern traction units, and the two are inter-dependant. The AWS cancelling button is used to cancel a TPWS brake demand once the train has come to a stand - The brakes won't release until you've done so.

Under current Rules, if AWS is faulty on a modern train, then the train is restricted to 50 MPH unless a competent person can be found to ride in the cab with the driver. That shows how important AWS is still seen to be. As a driver, AWS is wonderful because it acts to prevent an incident happening - eg, missing a precautionary aspect due to drowsiness or distraction. TPWS only intervenes when you've already messed up !!

AFAIAA There are no plans to phase out AWS from the British Railway System at this time.

NB: I'm not saying this as an arsey response, I'm just singing the praises of AWS. It might be old and unsophisticated, but most drivers have been saved alot of embarrassment by it. I love it.

The story of the creating of this new loco is worth reading if you have an hour or so to spare.

Yes, that's an excellent website. I've bookmarked it and will return there when I've got more time. Thanks for that.

Foggy

[hairyhandedfool]

TPWS is an add-on to AWS, it replaces AWS in that it incorporates it.

[Foghut]

Originally Posted by hairyhandedfool

TPWS is an add-on to AWS, it replaces AWS in that it incorporates it.

Exactly. A statement that TPWS is a direct replacement for AWS is misleading and wrong.

In the cab we still have the AWS cancelling button and the AWS sunflower. On the track we still have AWS magnets. If TPWS truly replaced the AWS hardware, it would be called TPWS.

We all know it's a lash-up, designed to be a poor man's version of ATP. The proof of this is that when the going gets tough and you neeed a safety system the most, ie: Degraded Working, TPWS has to be switched out because it isn't designed to handle complex situations.

I've lost count of the number of times recently when performing Single Line Working and Temporary Block Working where the TPWS is overridden. And yet the AWS continues to do the job it was designed for.

Hence my comments about AWS not being replaced.

(I've got a feeling that this one could run and run )

[John_142]

On the subject of AWS and ATP and TPWS as these are saftey eqiptemnt i have been wondering for some time now about the use of tokens as i belive they are called.

As i use the Ormskirk to Preston Line fairley regular and was wondering what is the token actually used for ie What is its pupose.

[Foghut]

Originally Posted by John_142

As i use the Ormskirk to Preston Line fairley regular and was wondering what is the token actually used for ie What is its pupose.

Well this is going off at a bit of a tangent to the discussion we were having about AWS/TPWS, but the pupose of a token is usually to give the authority to be on a section of single line. The token equipment is set up so that only one train can be in section at any time. The only way that signals can be cleared to allow the next train into section is by the previous train coming out of the section and its token being returned to the token apparatus, to prove that the line is now clear again and enable the interlocked signals to be cleared.

Although it's a clever arrangement, mistakes can still be made. I always think of the Abermule disaster when I think of tokens. http://www.bbc.co.uk/wales/mid/sites...ule_1921.shtml

Tokens can either be physical lumps of metal which are passed to the driver at the beginning of the section and 'surrendered' once the train comes out of section, or they can be virtual as in the the case of Radio Electronic Token Block (RETB) whereby a token is passed to and from the train electronically.

(I mentioned Single Line Working in one of my previous posts. This is a temporary arrangement whereby a Pilotman "on the ground" controls movement in both directions over a single line with the Signaller's authority, usually because engineering works are blocking one or more running lines. Here the Pilotman issues Single Line Working Tickets, which are a temporary form of token. As a driver these have to be cancelled once you have come out of the Single Line Section. One 'comforting' aspect for drivers is that it's a rulebook requirement for the Pilotman to ride with you on your train if you are travelling towards an obstruction. When this happens and the Pilotman is sitting next to you on the footplate you know you're doing it right !

HTH
Foggy