automatic warning system

[paulmblythe]

I am currently build an o gauge A3 with an A4 also on the horizon. I model the late BR period so the locos would be fitted with AWS gear. The bogies on both my kits have no provison for aws so will need modifying. I have a number of books containing photos of locos but none with a clear picture of the aws shoe on the front bogie (most seem to be in shadow or not clear enough. can anyone please point me in the right direction of photos or a drawing showing this. I have tried google and all the usual places but have come up with nothing. The drawings I have do not show it either.

[greenglade]

Hi Paul

Perhaps this picture from the NRM may be of help, there are others too if this is not enough..



regards

Pete

[John Palmer]

About the best photograph I have seen of an AWS shoe fitted to an A4 appears in Kichenside and Williams' 'British Railway Signalling', 1963 edition (the first, I believe). This is a good, sharp British Railways image of the front end of 60007 Sir Nigel Gresley, but I can find no trace of it being reproduced online. The best alternative I can offer is at http://www.davidheyscollection.com/page81.htm, which coincidentally contains a photograph of the same engine from the same viewpoint (at a later stage in his career). Unfortunately this online photograph is not as sharp as the book photograph mentioned, but nonetheless contains a reasonable amount of detail of the shoe and its mounting arrangement.

[notascoobie]

Hi Paul

Perhaps this picture from the NRM may be of help, there are others too if this is not enough..

regards

Pete

That's nothing like it, there's no NEM pocket!

Rgds,

Vernon

[paulmblythe]

thanks pete. that photo shows the bracket where the aws shoe fits on and will be very helpful. I have a few pictures I took at the great gathering of the a4s but the best one I have of the bogie is dominion of Canada which has had its aws gear removed for obvious reasons.

john there are some interesting pictures on that site. one of the problems I am having in getting a clear shot is that the bang plate which protects the aws gear from being bashed by the coupling gets in the way!

[StevieG]

I am currently build an o gauge A3 with an A4 also on the horizon. I model the late BR period so the locos would be fitted with AWS gear. The bogies on both my kits have no provison for aws so will need modifying. I have a number of books containing photos of locos but none with a clear picture of the aws shoe on the front bogie (most seem to be in shadow or not clear enough. can anyone please point me in the right direction of photos or a drawing showing this. I have tried google and all the usual places but have come up with nothing. The drawings I have do not show it either.

" About the best photograph I have seen of an AWS shoe fitted to an A4 appears in Kichenside and Williams' 'British Railway Signalling', 1963 edition (the first, I believe). This is a good, sharp British Railways image of the front end of 60007 Sir Nigel Gresley, but I can find no trace of it being reproduced online. .... "

I'm sorry that I cannot help with your main request Paul.
But in the interest of clarity, as future misconceptions can, over time, grow from small innocent inattentions to it, (and at the risk of accusations of pedantry), may I just say that, to my knowledge, the only true 'AWS' "shoe", (or ATC* shoe, as the GWR mostly called it), was that which formed part of the GW system (of 1904?), where the 'shoe' made physical contact with a long narrow, slightly humped, wooden 'ramp', in order to detect -
- a) the presence of a ramp; and
- b) whether or not the metallic strip along its top edge was electrically energised,
in order to determine whether to give an in-cab 'Clear' or 'Warning'.
This 'Western' system lasted at least into the 1980s, while being progressively replaced by the BR standard inductive AWS system over several years, and for a long time, certain members of certain classes of diesel loco had to be fitted with the 'Western' AWS system, either instead of, or in addition to, the BR system.

So; as I am very doubtful that an A3 would ever have been equipped for 'Western' AWS , the type of AWS item in question would, AFAIK, more correctly be called the 'Receiver', as it determines the giving of a 'Clear' or 'Warning' by means of (without physical contact at any time), detecting, and reacting to, magnetic fields of differing polarity emitted from the Permanent (and usually also the Electro*) rectangular (usually yellow) 'Inductors' (often called magnets) which, in pairs*, constitute BR standard AWS track installations.
I also know of the previously-mentioned photo in Kitchenside/Williams, and it is a good, clear one (seemingly a rare record).

* ( - "Automatic Train Control")
* ( - The purpose of some BR standard AWS installations is to always give a Warning (I won't elaborate here), in which case only a permanent magnet is provided.)

[ End of intrusion.]

[ Edited 09:55 - 10:17, 16/07/14, to add minor improvements to descriptions.]

[John Palmer]

StevieG, apologies, you are quite right to take me to task for use of the wrong nomenclature. I was aware of the difference between the Great Western's system based on physical contact with the ramp and the Hudd system based on magnetic principles. Perhaps my error reflects the fact that for most of my life my homes have been within sight (or at least earshot) of the Bristol & Exeter main line and I am consequently more familiar with GW systems.

[StevieG]

StevieG, apologies, you are quite right to take me to task for use of the wrong nomenclature. I was aware of the difference between the Great Western's system based on physical contact with the ramp and the Hudd system based on magnetic principles. Perhaps my error reflects the fact that for most of my life my homes have been within sight (or at least earshot) of the Bristol & Exeter main line and I am consequently more familiar with GW systems.

No apology expected or needed John, and no personal criticism intended : Just taking an opportunity to possibly prevent a future reader or two understandably straying onto one minor path of misunderstanding which occasionally over time can become misquoted as fact.
And I've even just made a couple of minor tweaks to my own post, to improve descriptions.