GWR Steam Railmotor Chassis

Jeremy Suter
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GWR Steam Railmotor Chassis

Postby Jeremy Suter » Sat Feb 11, 2017 7:38 pm

Some years ago I built the Mallard GWR Steam Railmotor in 7mm for a friend and always thought I would like one in 4mm.
I have seen OO ones made up and I don't like the look of the chassis. its been simplified too much and now there is a real one running around the preservation circuit.
IMAG0002.JPG

The chassis is not just two side frames and some spacers.
The boiler has to be slotted in between the frames and they have to fit round it. It's also not central between the axles it is off set by 2 inches to the rear, not much but to fit the slide bar bracket and the body mounts in you need all the space you can get. There are no Rivets and Brakes on the Mallard kit.
IMAG0001.JPG

With all this in mind I have set to drawing the chassis up and trying to make it as close as possible to the real thing. I have done two drawings one rigid and one sprung. These drawings are only for the frames and associated parts. The Valve Gear, Coupling Rods and the Cylinder Covers will be on thinner material
IMG_1845.JPG
IMG_1846.JPG
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Penrhos1920
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Re: GWR Steam Railmotor Chassis

Postby Penrhos1920 » Sat Feb 11, 2017 8:18 pm

Will this fit the Kernow railmotor?

Jeremy Suter
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Re: GWR Steam Railmotor Chassis

Postby Jeremy Suter » Sat Feb 11, 2017 8:42 pm

Will this fit the Kernow railmotor?
I've not got the Kernow railmotor, so I do not know if it will fit. I saw it online last year and was not very impressed with it.

I will be mounting the chassis just like the real thing, by the brackets which come down from the solebar to a beam which goes under the chassis to the other side (this is how it was done in the 7mm version).
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Jeremy Suter
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Re: GWR Steam Railmotor Chassis

Postby Jeremy Suter » Sat Feb 11, 2017 9:41 pm

Etches now received. Front and back pictures are shown.

IMG_1850.JPG
IMG_1849.JPG


I had the drawing etched twice one in 15 thou as designed and the other in 18 thou. As I was unsure if it would be strong enough. At the moment I think the 15 thou will be fine, but time will tell. A couple of things will need to be changed they are the size of the rivets will need to be enlarged as the undercut has eaten too far into them and also one of the holes in a lever has etched bigger than the outer ring in the 18 thou. version. one or two other minor errors have been spotted as I have missed a slot out of the cylinder front so will have to drill out for now.
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Ian@Exton
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Re: GWR Steam Railmotor Chassis

Postby Ian@Exton » Sat Feb 11, 2017 9:51 pm

This looks excellent, Jeremy.

I am part way through building a railmotor myself, using the original Mallard chassis etchings and castings, but have put it to one side for the moment while thinking about the problems of making cosmetic frames and including the suspension links.

The idea of getting closer to the prototype and supporting the body properly is appealing, if there is enough room to do it in 4mm.

Have you designed the etches with a particular motor and gearbox in mind? Are you intending to mount them so that they could be hidden within the vertical boiler?

I would be very interested if you were to make the etchings available, and in the meantime I look forward to following your progress on this thread.

Jeremy Suter
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Re: GWR Steam Railmotor Chassis

Postby Jeremy Suter » Sat Feb 11, 2017 10:29 pm

Have you designed the etches with a particular motor and gearbox in mind? Are you intending to mount them so that they could be hidden within the vertical boiler?

I would be very interested if you were to make the etchings available


Hi Ian
I will be making the chassis etc. available in time.
At the moment I have a pile of small Chinese motors which I want to use . As for the gear box I am hoping to use Highlevel gears in my own gearbox and standing vertically inside the boiler driving the rear axle, although I have not checked but Highlevel may already do a gearbox which will fit.
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Craig Warton
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Re: GWR Steam Railmotor Chassis

Postby Craig Warton » Sat Feb 11, 2017 11:53 pm

Jeremy,

That looks like an excellent solution to the problem that is that Mallard rail motor!

In the fullness of time, should you make these available, you can expect an order from Australia.

Regards,

Craig Warton

Jeremy Suter
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Re: GWR Steam Railmotor Chassis

Postby Jeremy Suter » Sun Feb 12, 2017 8:17 am

Hi Craig

Keep watching this space I will be making them available when I get it wright. The same with my other workbench project of the Diagram V2 parcels van which is now only awaiting the production etch testing.
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martin goodall
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Re: GWR Steam Railmotor Chassis

Postby martin goodall » Sun Feb 12, 2017 5:18 pm

Jeremy Suter wrote:
Will this fit the Kernow railmotor?


I am under the impression that the Kernow-commissioned SRM is still some way off. No doubt it will be subject to further refinement of the masters before it goes into production.

Jeremy Suter
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Re: GWR Steam Railmotor Chassis

Postby Jeremy Suter » Sun Mar 05, 2017 8:52 am

I now have started to put together the 18 thou test etch, and feel that it will be better in the 15 thou as originally designed.
I am using the same bearings as in the Brassmasters kits and they fit nicely in the etched slots and are to be sprung from above.
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andrewnummelin
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Re: GWR Steam Railmotor Chassis

Postby andrewnummelin » Sun Mar 05, 2017 7:10 pm

I'm really looking forward to following this thread as I'm about to start on a similar project and avoiding reinventing the wheel is going to be really important if I am to achieve my target. In particular, the bogie suspension and the valve gear are going to be interesting.
I can't check at the moment as all my books are still boxed after a house move, but if the unit proves suitable for the Barry and Cardiff motors there'll be a couple of etches coming my way when you make them available.
Regards,

Andrew Nummelin

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jsherratt
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Re: GWR Steam Railmotor Chassis

Postby jsherratt » Fri Mar 10, 2017 4:40 pm

Hello Jeremy.

To add to the above. I have one of these Mallard GWR Railmotors hidden away in a box waiting to be built one day.

The etch you are working on looks splendid.

You can put me down for one of your etchings as well when they become available! :thumb

John

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Horsetan
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Re: GWR Steam Railmotor Chassis

Postby Horsetan » Sat Mar 11, 2017 1:16 pm

Jeremy Suter wrote:
Have you designed the etches with a particular motor and gearbox in mind? Are you intending to mount them so that they could be hidden within the vertical boiler?

I would be very interested if you were to make the etchings available


Hi Ian
I will be making the chassis etc. available in time....


Excellent! :thumb

Put me down for two sprung ones, please.
That would be an ecumenical matter.

Phil O
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Re: GWR Steam Railmotor Chassis

Postby Phil O » Sun Mar 12, 2017 9:42 am

Horsetan wrote:
Jeremy Suter wrote:
Have you designed the etches with a particular motor and gearbox in mind? Are you intending to mount them so that they could be hidden within the vertical boiler?

I would be very interested if you were to make the etchings available


Hi Ian
I will be making the chassis etc. available in time....


Excellent! :thumb

Put me down for two sprung ones, please.


And one for me, please.

Jeremy Suter
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Re: GWR Steam Railmotor Chassis

Postby Jeremy Suter » Tue Mar 14, 2017 10:18 pm

Thanks to all for the expression of interest in having a kit

I have just sent the second test etch to the etchers. A few very minor changes to the drawing with the main one being that the Motion Bracket did not allow enough space for the coupling rods to go round (the test wheels I am using are Gibson 4' (16mm) with 3.66mm throw on them) I got these wheels as they have the biggest throw and will need maximum clearance.

I am hoping to use a set of Sharman wheels on the final model which I have had for many years. Gibson do make a 3'11" wheel with a 2.6mm throw and 12 spokes which would be the correct throw for the Railmotor, and I think I will try a set for size, only .4mm too small. It may well be that these are best in the end.

IMG_1860.JPG


Anyway I have now put together the 15 thou version and yes it should be fine the photo shows it with the boiler mount and rear brakes added but the lower part of the boiler needs to be shorter as there is a gap between the top and side.

IMG_1861.JPG


This photo shows where the motor I intend to use should go and will drive the rear axle.
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Andy W
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Re: GWR Steam Railmotor Chassis

Postby Andy W » Thu Mar 23, 2017 10:04 am

It's very impressive jeremy. I'm designing a Midland version so know how tricky these things are. The scale of the valve gear etc etc. How do you plan to attach the unit to the floor, and will there be any side play/swing?
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Jeremy Suter
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Re: GWR Steam Railmotor Chassis

Postby Jeremy Suter » Thu Mar 23, 2017 8:13 pm

Quote


Postby Andy W » Thu Mar 23, 2017 10:04 am

It's very impressive jeremy. I'm designing a Midland version so know how tricky these things are. The scale of the valve gear etc etc. How do you plan to attach the unit to the floor, and will there be any side play/swing?

Thanks Andy for the interest I intend to mount the chassis to the floor just like the real thing by a pair of bars which travel underneath the chassis and connected to both the chassis and the floor by rods.

2.jpg

The rods running to the chassis will be not rigid so that there should be movement to go through curved track and turnouts although not sure how tight yet.
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Andy W
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Re: GWR Steam Railmotor Chassis

Postby Andy W » Fri Mar 24, 2017 9:40 am

Thanks Jeremy. It makes me want to look out for a Mallard kit.
Make Worcestershire great again.
Build a wall along the Herefordshire border and make them pay for it.

GWSGMember
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Re: GWR Steam Railmotor Chassis

Postby GWSGMember » Wed May 17, 2017 12:18 pm

Any update on this as I'm very interested in purchasing two or three sprung ones for my Mallard and Worsley SRM etches models.

kelham
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Re: GWR Steam Railmotor Chassis

Postby kelham » Wed May 17, 2017 3:22 pm

Jeremy, please add my name to your list as I have a couple of unstarted Mallard kits sitting in my "if I'm still fit enough when I finally retire" drawer.


Richard Kelham

Jeremy Suter
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Re: GWR Steam Railmotor Chassis

Postby Jeremy Suter » Wed May 17, 2017 7:20 pm

Thanks for the comments so far.
I have not given up on the project but spare modelling time is in short supply at the moment. Although I have another project on the bench which I have just finished building. This is a test etch for Brian Morgans GWR Iron Mink it needed a few extra pieces which I had etched and has gone together very well. Not sure what to do about this project at the moment but its made into quite a nice model. Just needs Painting and Buffer heads now.
IMG_1867.JPG

With that finished it should give me a chance to get back to the Railmotor.
I have done a few things the Valve gear has been etched in 12 thou nickel silver, but have not had a chance to put it together yet. Before I start I need to make rivets as it will require rivets with .5mm shanks and .9mm heads. I did make a dozen a few weeks ago and have since mislaid them.
IMG_1870.JPG

I have also now drawn up the underframe for the Diagram Q Gloucester Built Unit and has now gone for etching, again in 12 thou nickel silver. I hope to get it back by the weekend.
IMG_1871.JPG
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Horsetan
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Re: GWR Steam Railmotor Chassis

Postby Horsetan » Wed May 17, 2017 8:56 pm

Andy W wrote:Thanks Jeremy. It makes me want to look out for a Mallard kit.


They are very expensive when they come up on eBay :shock:
That would be an ecumenical matter.

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Re6/6
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Re: GWR Steam Railmotor Chassis

Postby Re6/6 » Thu May 18, 2017 7:24 am

Coopercraft do the body etches. Last time that l saw Paul Dunn at a show the former 'Blacksmith/Mallard(?)' etches were on sale.

It would appear that the etched side of the business is still functioning. If one can't get to a show, unfortunately contacting via e-mail or ordering from the website can be problematical.

http://shop.cooper-craft.co.uk/index.php?cPath=83_89
John

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Craig Warton
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Re: GWR Steam Railmotor Chassis

Postby Craig Warton » Thu May 18, 2017 9:01 am

Jeremy,

is there any possibility of the Iron mink seeing the light of day? I started cutting up a ratio one to look like the real thing and ended up with a big collection of parts to reassemble. That brass one is something that looks more my tastes - and the rail motor chassis of course.

Regards,

Craig

Jeremy Suter
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Re: GWR Steam Railmotor Chassis

Postby Jeremy Suter » Thu May 18, 2017 6:51 pm

Is there any possibility of the Iron mink seeing the light of day?
Craig




Hi Craig
I shall be getting some more of these test etches, as I would like a few more myself . Only thing I need to do for you would be right some instructions for you as its not so straight forward a kit one or two things need to be filled off.
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