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GWR/WR Automatic Train Control Equipment


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I'm currently on with a P4 ex-Mainline Dean Goods loco 2538 which was an Oswestry loco and therefore OK for my area of interest.  Looking at photos, mainly in Bradford Barton books, this loco (amongst other Dean Goods) had a very prominent ATC contact shoe under the front buffer beam which I would like to represent.  I can't find a full length offering in the trade and have no qualms about scratch building one - but where can I find a drawing or a GOOD photo(s).  There are photos in many books which show the front buffer beam of this and other locos but, owing to the positioning of the device, they are all in shadow and at best only show the front.

 

If anyone knows of a suitable trade casting etc. or where I could find a drawing I would be very grateful.

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Thanks for the replies so far.  I've seen the Martin Finney casting but, to me, it seems a bit 'short' vertically.  The model photos from John are good.  I take it these are O gauge?  A front view could be useful if you have one John.  I reckon I could cobble something up based on these.  (BTW, not been aware of the guard iron/buffer beam braces before) All the prototype ones are similar to ones I have in various books - rather indistinct!  However, I still have quite a few books (ie - lots!) to go through.  For such a common item I'm rather surprised to find such a small amount of info.

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Wow!  thanks for this Justin.  There's a lot to take in there!  Possibly a bit of overkill for what I'm looking for but I'll look into it in more detail when I get the chance.

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16 hours ago, 5050 said:

Thanks for the replies so far.  I've seen the Martin Finney casting but, to me, it seems a bit 'short' vertically.  The model photos from John are good.  I take it these are O gauge?  A front view could be useful if you have one John.  I reckon I could cobble something up based on these.  (BTW, not been aware of the guard iron/buffer beam braces before) All the prototype ones are similar to ones I have in various books - rather indistinct!  However, I still have quite a few books (ie - lots!) to go through.  For such a common item I'm rather surprised to find such a small amount of info.

 

Hope these help

 

DSC05869.JPG.7463c21c8bd916e4a46c2db5af1b5122.JPG

 

 

DSC05870.JPG.59a916f1bac936cd75de24950eb1bef7.JPG

 

DSC05871.JPG.3c6ad8643010d8c3ec739959f4e32cd0.JPG

 

 

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I've spent an interesting hour or two trawling through a range of photo books (some of which I haven't visited for several years!) and, as well as being sidetracked with some of the photos, I have begun to formulate a general idea of the design.  As Miss Prism says above, there is a definite variety in design but the Dean Goods seems to share the same one as 43xx, 47xx, 90xx so this is the one I'll have a go at drawing up with guesstimated dimensions.

 

Sorry to say that I haven't seen any fittings that closely relate to the one on on RossPop's Dean Goods.  I suppose that the one supplied must have been based on a real one- but on which loco?

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4 hours ago, 5050 said:

Sorry to say that I haven't seen any fittings that closely relate to the one on on RossPop's Dean Goods.  I suppose that the one supplied must have been based on a real one- but on which loco?

 

Probably 2538, a late survivor, but I think most of the ones fitted to Dean Goods were the same. Here's 2571 at Didcot in 1936:

 

2571-didcot-1936-cropped.jpg.2231992146c70410e8b40b5b25b537c4.jpg

 

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I've started to build a 3D model from the engineering drawings in Justin's post:

 

ATC3.png.b2bdf1a171492f1bf8d0dc477cbacd45.png

 

I have mainly concentrated on the castings so far and there's still a lot to do - rounding off various corners, adding nuts & bolts, etc.

 

(Don't worry about the colours or extra lines where they shouldn't be - they are all just to help to see what I'm doing during construction.)

 

It's very satisfying to be able to create something from drawings that are around 85 years old and to see the shapes come to life in a way that the original draughtsman could not possibly have imagined!

 

Notice that the grey shapes are fibre pads and that fibre bushes and washers are specified (not drawn yet) with all 8 bolted connections to provide electrical isolation between the device and the loco frame.

 

As Miss P. said right at the top, the device was common to all locos but the way it was mounted differed between classes.

 

Edited by Harlequin
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On 10/10/2020 at 22:45, Miss Prism said:

 

Probably 2538, a late survivor, but I think most of the ones fitted to Dean Goods were the same. Here's 2571 at Didcot in 1936:

 

2571-didcot-1936-cropped.jpg.2231992146c70410e8b40b5b25b537c4.jpg

 

It's 2538 I'm doing.  It's the one that Mainline numbered and, as an Oswestry loco, is fine for me.  It has the 'normal' design of apparatus as the photo you've posted.  I'm currently trying to 'cobble up' a version in plastic and Harlequins's drawing will certainly help in this.  However, I think I might have got a couple of the proportions wrong so I may have to start again!

 

Harlequin - is your drawing a prequel to a 3D printed version??

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32 minutes ago, 5050 said:

Harlequin - is your drawing a prequel to a 3D printed version??

 

Yes, that's the idea. I hope to make the model available to the community in some form or other.

 

I'll send you the Sketchup file when I've made a bit more progress if that would help.

 

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5 hours ago, 5050 said:

It's 2538 I'm doing.  It's the one that Mainline numbered and, as an Oswestry loco, is fine for me. 

 

2538-oswestry-31mar57-small.jpg.e3b3a5f6408bc38692f630040a1d5cc4.jpg

 

On shed at Oswestry, 31 March 1957. It ran with a 2500g tender in BR days.

 

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Looking at Harlequin's rendered image (which I realise wasn't complete when posted) there is a significant part missing that is not included in the original GWR drawings as part of Justin's post.  This is the  bar that goes across the front of the apparatus, attached to brackets bolted to the sides.  It doesn't seem to have any part of the function of the apparatus - but was it added as an afterthought, perhaps to protect the apparatus from potential damage by a swinging coupling?  Clearly seen here on a 47XX on Old Oak common, a detail taken from a P J Lynch photo.

 

645760352_47xxATCapparatus.jpg.e1c5baff8f31c7c9dbf8e53915c2accf.jpg

 

Will you be including this in your 3D rendering Harlequin?

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1 hour ago, 5050 said:

Looking at Harlequin's rendered image (which I realise wasn't complete when posted) there is a significant part missing that is not included in the original GWR drawings as part of Justin's post.  This is the  bar that goes across the front of the apparatus, attached to brackets bolted to the sides.  It doesn't seem to have any part of the function of the apparatus - but was it added as an afterthought, perhaps to protect the apparatus from potential damage by a swinging coupling?  Clearly seen here on a 47XX on Old Oak common, a detail taken from a P J Lynch photo.

 

645760352_47xxATCapparatus.jpg.e1c5baff8f31c7c9dbf8e53915c2accf.jpg

 

Will you be including this in your 3D rendering Harlequin?

Another useful photo, thanks. (I wish I could see the back of one!)

 

The bar across the front seems to be quite common and is part of the mounting, rather than part of the device itself. I think your idea about it protecting the device from being knocked by the coupling might be spot on.

 

I will try to model this kind of mounting. I've got a cunning plan to combine it with an NEM tongue so that it will plug into an NEM socket on RTR locos. :smile_mini2:

 

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Thinking about seeing the back of one, I just remembered that I took lots of photos underneath Caerphilly Castle the last time I was at Steam...

 

All I found was this:

IMG_20190620_140814.jpg.8bdf3f1b259ad22710708d3165fe659e.jpg

 

D'Oh! Another partial view of the front!

 

Edited by Harlequin
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Here's the latest version:

ATC9r.png.ef212c1305667706de9e6c6cf07f002a.png

Fillets in all the internal corners of the castings.

Corrected some mistakes and added some details.

Nuts, bolts, washers and bushes.

 

I know some of this small stuff will hardly be visible at 4mm scale but it's good to do it properly so that the model could be used at any scale. (I'm drawing it actual size - it's about 33 inches high.)

 

Edited by Harlequin
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I've had a go at cobbling up a model based on the GWR drawings, photos and Harelquin's renderings - and here it is -

 

437937433_ATCApparatusmode_Al.jpg.f7cf1229b89c972d6ef9ac1a509cca8c.jpg

 

It is extremely small in 4mm scale!  The photo is well over life size and makes it look very crude but it should be OK with a good coat of dirty black.  I reckoned on the overall length from buffer beam down to be 10mm give a thou or two so Harlequin's 33mm overall seems right.  I expect Harlequin's 3D printed versions to be a lot more accurate than my rather crude effort - although it is the first model of one I've seen.

 

Please don't ask me to make another on commission.  You won't be able to afford it.......................

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Here's the next update:

ATC11r.png.8ca627d5ba32305bc38473590709c920.pngATC11s4r.png.00c1e625491f5d83a957cdd99f286ee8.png

 

The shape of the side mounting plates is a bit of an educated guess. I think I see the angled rear in some photos. The electrical cable passes through one of the holes to connect to the ATC device and pick up voltage from the ramp.

I changed some of the washers because I realised that the engineering drawing was showing spring washers in many places.

All the bolts are now oriented correctly. Notice that one of the four bolts connecting each side to the mounting plate is reversed. That's exactly as drawn because the body of the device would prevent a bolt being inserted from the inside in that position.

 

And I realised what the front guard bar is really for. It is there to prevent the coupling making electrical contact with the device and giving wrong indications in the cab. Note that the guard is fixed to the outside of the mounting, thus electrically connected to the loco frame and insulated from the device.

 

Edited by Harlequin
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Further small update:

ATC12r.png.8c3a7a08dabefdf2c4430881bbbd6a80.pngimage.png.827ec784d3045979310702adf0b099a5.png

 

Added the connecting cable (more correctly the trunking) and plugs in the holes on the opposite side. The "plugs" might be bolts but it's not clear so I've just added non-descript cylinders covering the holes.

 

Edited by Harlequin
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