GWR Railmotor

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David B
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GWR Railmotor

Postby David B » Tue May 17, 2011 9:36 am

Rather than hijack the 27xx / 57xx thread, I thought it better to start a new one in response to Howard's enquiry and Paul's invitation.

My railmotor is coming on - slowly! It is a Mallard kit of a Diagram Q (59' 6") which I bought and started back in the 1980s when I was clueless about soldering brass. I have therefore dismantled it and started again (which is why it looks 'used'), but converted it to P4 which has been quite a learning curve. The chassis is new except for the cylinder block (which had to be carved out and widened) and the valve gear. A new mounting has been devised.

I also replaced the trailing bogie with a Masokits sprung one. The original was cast white metal which a) was OO and b) not square. I gather Blacksmith have a much better one with their 70' Railmotor kit now; the Diag Q is no longer on their list. The Masokits bogie is lovely, was easy to assemble and just needs cosmetic sides adding.

I am currently working on the passenger steps which are just too deep to fit with the truss rod through them, so they are now being shortened by 2mm. They articulate but once fitted, I will lock them up as there seems little point in having them swinging in & out and I feel they will be safer fixed. Then it's the little bits and fitting out the inside . . . and getting the power unit to run better.

The book Great Western Steam Railmotors by John Lewis has been invaluable in checking measurements and making the kit.

If anyone else has made or is making this kit, please chip in with your comments, hints, questions and photos. Anyone making an autocoach?

David

Railmotor.jpg
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Railmotor valve gear.jpg
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martin goodall
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Re: GWR Railmotor

Postby martin goodall » Tue May 17, 2011 9:32 pm

I have one of these kits to build when I can finally pluck up courage, so David's note was very encouraging. (More please, David).

By the way, what driving wheels have been used?

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David B
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Re: GWR Railmotor

Postby David B » Tue May 17, 2011 9:47 pm

Martin,

The wheels are Gibson (as are the replacement frames), but they may be a bit large. The diagram that comes with the instructions (dated 1974) says the valve gear is shown (on the drawing) as assembled from the kit. It goes on to say the wheels are 3' 9" diameter with a 9" throw but that they were later changed to 4' 11/2". I put the larger ones on as the wheels on the diagram measure just over 16mm and found that the valve gear fouls the solebar so had to do a lot of fettling to get the motor unit to clear the body and the buffer height right.

On reflection, I think the smaller wheels might have been better. Having got this far, I am not inclined to alter it!

David

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Dave K
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Re: GWR Railmotor

Postby Dave K » Wed May 18, 2011 6:54 am

David,

Like Martin I (in a moment of madness) bought one of the short railmotor's and every now and then have a quick look in the box and decide that there is something else I should be getting on with e.g. a 517.

However I do remember seeing someone on the S4urm demo stand who had scratch build the motor bogie, and a lovely job it was too. Also I'm sure I remember a trader who had the prototype etch for a replacement motor bogie, in 7mm, but with some 4mm drawings on the bases that, like me, "there must be hundreds of people out there who also look in the box and see the etches and castings for the motor bogie and think, one day I will get round to build this". However, that was the last time I saw it or even the trader at S4urm.

Would love to see more photos of the motor bogie and maybe see whole thing at Leatherhead in September :?:

Philip Hall
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Re: GWR Railmotor

Postby Philip Hall » Wed May 18, 2011 7:42 am

David,

Congratulations on a lovely piece of work. The valve gear is one of those watchmaking nightmares so your eyes must be much better than mine. I remember something by the late John Harrison in an old Railway Modeller on one of the incarnations of his Torpoint Branch, and there was a picture of a railmotor, which he said was usually referred to as 'Caw, look at the valve gear!' There was also a reference to 'Bulliver rides again...' which I don't understand at this distance in time. Someone on here will no doubt know (Gerry Beale, maybe?)

Anyhow, the wheels. My Sharman book says there were two sizes. The 1903 ones had 3'6", 10 spoke, 8" throw, crankpin between spokes. The 1904 ones had 4'0", 12 spokes, same throw and pin position. So if yours is 1904 you're OK, but if you want to be fussy, it looks as though the crankpin's in the wrong place.

What have you used for the motor and gearbox?

Philip

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David B
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Re: GWR Railmotor

Postby David B » Wed May 18, 2011 7:59 am

The diagram Q Railmotor was built in 1905/6. Lewis reproduces diagrams which gives a wheel diameter of 4'.

The motor is a Mashima with a High Level gearbox.

I nearly bought another one at Expo EM but someone else made my mind up for me! I put off making the railmotor for some time because of the valve gear, but having done it once, I wouldn't mind doing another. It's the initial fear that has to be overcome. It was Tony Wright at a Missenden weekend who gave me the push with his demonstrations. I filed down lace pins and used paper washers. Blacksmith used to list the valve gear separately, so someone may well have a spare fret lying around.

I'll see about some more images of the bogie.

David

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Will L
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Re: GWR Railmotor

Postby Will L » Wed May 18, 2011 9:22 am

Philip Hall wrote:...There was also a reference to 'Bulliver rides again...' which I don't understand at this distance in time..p


Bulova is an American watch making company, memorable from under the bed cloths because they advertised on Radio Luxembourg. They claim to have made the first electronic watch.

Will

martin goodall
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Re: GWR Railmotor

Postby martin goodall » Wed May 18, 2011 9:43 am

I can reassure David that 4' 1.5" is the correct wheel diameter. So no need to contemplate any change. (The 3'9" wheels were not used on the Q Diagram railmotors.)

Philip's reference to 'Bulliver' relates to the nickname given to the Ashburton branch train. (No-one has ever been able to explain the origin of the name.) I am not aware of steam railmotors having been used on the Ashburton Branch; the name seems to have been applied to the branch auto-train - a 517 (later 48XX) and autotrailer, with a second autotrailer added at peak times. Three-coach trains of 4-wheelers were used on the branch until the late 1920s/c.1930, when the autos took over.

Bulwell Hall

Re: GWR Railmotor

Postby Bulwell Hall » Wed May 18, 2011 4:07 pm

Sorry to crash in on this thread but it was good to see John Harrison's name appear in Philip's post. John was not a finescale modeller as all the Torpoint layouts were resolutely OO gauge - at least they were until he went to O gauge - but like so many of the layouts of that period they had such character! The various Torpoint layouts contained elements of a number of GWR branchlines in the West Country but the Ashburton Branch was one of Johns favourites. I no longer have my old 1960s Railway Modellers so cannot access his articles but I would guess that he has a 48xx and trailer which, as Martin has rightly said, was used on the Ashburton branch from the early 1930s until closure to passengers in the 1950s and was probably what he meant by "Bulliver rides again".

John was a Bristolian born and bred and his writings in Model Railways in the 70s were well constructed and very enjoyable. He wrote a series of articles on building the Ashburton Branch "big engine" which contained references to Driver Bill Cartright - the Ashburton top link. The "big engine" by the way was No.4405 - a 44xx 2-6-2T!! During my college days in the early 1970s I lodged just around the corner from John - in Horfield, Bristol - and was invited to regular meetings at John's house in Sefton Park Rd. when we operated Torpoint. One of the other individuals who regularly attended those meetings long ago was a young chap called Tony Reynolds! Sadly John passed away probably more than twenty years ago now but I am pleased that his layouts are still remembered with such fondness and his work did much to foster the impression that GWR BLTs dominated the modelling scene in the 50s and 60s.

See what you have done Philip! I hope the above is of some interest and are not just nostalgic ramblings!

Gerry Beale

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David B
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Re: GWR Railmotor

Postby David B » Wed May 18, 2011 4:15 pm

As requested by David K, images of the power unit.

I found it helpful to lay the pieces out once I had de-cusped the etches. Be aware that the eccentric cranks off the rear wheels are different and have a D-shaped hole to fit the flat you file on the crankpin. I found this out afterwards! The slide bar support has been cut in half to fit the P4 frames, but do check measurements before taking this drastic action. It required a lot of filing in places to make it fit, especially against the sides of the frames. I made mistakes both here and with the cylinder assembly which necessitated a partial dismantling (with the valve gear intact) before reassembling again slightly narrower. (The brass wire is functionless - it crept in to have it's picture taken.)

valve gear.jpg
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What is not clear from the pictures is the mounting arrangement. The original consisted of a metal 'sling' which bolted to the floor of the railmotor and passed outside the frames to a central bearing plate underneath the chassis on which it swivelled (rather similar to the way the pilot is slung in a hang glider). I modified this with a new 'sling' which passes down each side of the motor and underneath it to bear on top of the pickup plate inside the frames. This way it is not seen. The motor goes over the bracket. I am not entirely happy with the arrangement; others may well devise something better.

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Bulwell Hall

Re: GWR Railmotor

Postby Bulwell Hall » Wed May 18, 2011 6:09 pm

David

Having hijacked your thread earlier I should also have added that your steam railmotor is coming along very nicely. You are a brave man tackling that valve gear!

I too had one of these in my kit stash but never got round to starting it - I went 7mm scale and sold it which was one way of avoiding having to build the valve gear. Indeed it may have been you that bought it! Now that I have returned to 4mm I am modelling the post-war period so a railmotor is not suitable,

Just in case it has escaped anyones attention the Great Western Society will be unvielling their newly restored steam railmotor to the public on Saturday, 28th May. Why not go along to Didcot and experience something that has not been seen or heard since 1935 unless you were lucky enough to have been at Llangollen earlier in the year.

Gerry

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HowardGWR
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Re: GWR Railmotor

Postby HowardGWR » Wed May 18, 2011 9:14 pm

What a lovely and interesting thread. I didn't want to batt on about GWR on this forum, but in the modelling sense, Ii had an idea resulting from your excellent efforts David.

The steam rail motor has a vertical boiler (I suppose we might call it a coffee pot?). Thus, perhaps with the aid of one of those nifty gear boxes, as from High level, it occurred to me that the can motor could be mounted vertically and be treated to simulate the real thing.

Can anyone see a snag with this notion?

My other thought has to do with operation. Having seen the resurrection in operation climbing the bank at llangollen, I am still recovering from the amazement at the power and acceleration of the vehicle. Do have a look at it on Youtube.

So it would be an amusing experience at a show to be criticised by someone for racing it out of the station, just to retort haughtily, 'oh but that's how they went' .

I am left a bit cold by the repeated restorations of Collett engines, to be honest, but this was something else and a great way to educate about a lost past.

David, I do hope you get it running and exhibit it on Clutton, as I'm sure (?) that Tim would love to display it. :)

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Dave K
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Re: GWR Railmotor

Postby Dave K » Thu May 19, 2011 5:26 am

Thanks David for those pictures of the motor bogie.

Like Howard I am hoping, if I get round to building it, to try to mount the motor vertically like in the real thing.

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David B
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Re: GWR Railmotor

Postby David B » Thu May 19, 2011 7:52 am

Howard wrote: The steam rail motor has a vertical boiler (I suppose we might call it a coffee pot?). Thus, perhaps with the aid of one of those nifty gear boxes, as from High level, it occurred to me that the can motor could be mounted vertically and be treated to simulate the real thing.

Can anyone see a snag with this notion?


I like the idea too and thought about it after I had bought the motor but before I fitted it. I found the motor was in the way of the pivot point for mounting the unit. I also tried different combinations of the High Level gearboxes using the transparency that came with the Digest Sheets.

It may be possible to mount the motor vertically if someone can devise a different way of attaching the power unit.

David

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HowardGWR
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Re: GWR Railmotor

Postby HowardGWR » Thu May 19, 2011 8:41 am

The other thing that springs to my mind concerns rail motor operation. Assuming the layout involves a terminus (which of course Clutton would not), how does one niftily turn the thing around? I've made the same point about auto trains, where one needs to change head and tail lamps at a terminus and if one has model people, the driver has to vanish from the trailer and reappear in the engine alongside his mate. I suppose Fairford is a good cop-out as the train can disappear off to the rear while the switch takes place.

I won't go into goods yard operations, where loaded vehicles should not be returned to consignors still loaded, etc (that's another thread).

Bulwell Hall

Re: GWR Railmotor

Postby Bulwell Hall » Thu May 19, 2011 9:13 am

Surely the whole point of a steam railmotor is that it did'nt have to be turned round at a terminus? Swop over the head and tailamps and away you go again!

To be pedantic for a moment, so far as I know Fairford was not one of those lines on which steam railmors or auto trains ever worked probably because it was a lengthy run from Oxford where the services originated. Neither was the Bristol & North Somerset line through Clutton, to the best of my knowledge, one of thier haunts but they could have been found just down the line at Hallatrow where, for a few years, they worked services over the line to Camerton and Limpley Stoke.

Gerry Beale

martin goodall
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Re: GWR Railmotor

Postby martin goodall » Thu May 19, 2011 3:55 pm

On the Fairford Branch, the usual passenger acommodation in GWR days was a 3-coach set of non-gangwayed bogie stock (often clerestoreys) - usually Van Third, Compo, Van Third. Motive power (again in GWR days) would have been a Metro tank, either the medium or large variety.

In BR days, 2-coach trains were more often seen, usually ex-GWR Colletts or Hawksworths, sometimes corridor stock, especially in later years. After the disappearance of the Metro tanks in late 1940s, 54XX panniers took over most of the passenger services on the Fairford Branch, although 8750 panniers and Collett Goods (2251) were seen on passenger trains in the years before closure in 1962.

As Gerry pointed out, the 25-mile run between Oxford and Fairford made it unsuitable for railmotors or auto-trains. The allocation of SRMs to Oxford seems to have ceased in about 1916. Autotrains were seen (but not until the early 1930s) on the Woodstock Branch and Abingdon Branch. But I believe the SRMs did work on these two branches up to about 1916.

(End of history lesson!)

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HowardGWR
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Re: GWR Railmotor

Postby HowardGWR » Thu May 19, 2011 6:18 pm

Yes of course I knew all that but I was remiss in not stating that I assumed that they nearly always had an extra coach added, or indeed a van. This of course slowed them down and led to the auto train. I only cited Fairford due to its curious extension beyond the last station which of course was not intended to be only that. This was an example I could imagine that would give a 'fiddle yard' opportunity.

I still don't see how you avoid the hand of god with auto trains. Glad to see everyone is on the ball here. Phew!

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Tim V
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Re: GWR Railmotor

Postby Tim V » Thu May 19, 2011 7:14 pm

Head and tail lamps? Very few layouts sport trains with those, I can't think of any exhibitions where I've seen the lamps being exchanged at the terminus.
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IANATEXTON
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Re: GWR Railmotor

Postby IANATEXTON » Thu May 19, 2011 7:34 pm

With railmotors (and auto trains come to that) I really don't think we need worry about changing the lamps round. From what I can see in period photos it isn't that easy to distinguish a headcode lamp from a tail lamp - in daylight hours. They would both, in David's period, have red bodies and the lenses would be pretty dark in colour - they were certainly not like the brilliants one sometimes sees when modellers do actually equip their trains with lamps.
So I think the main thing would be to put a member of the loco crew in each end of the railmotor.
(It's just a pity I forgot to put a figure in the driving end of my auto-trailers!)

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David B
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Re: GWR Railmotor

Postby David B » Thu May 19, 2011 7:57 pm

Thanks, chaps, for the discussion on operations. I am sure this all helps with more prototypical running on a layout.

However, before one can run a railmotor, one has to build one! Going back to my original posting, has anyone else out there, perhaps who has made one, got any observations, comments or suggestions to make regarding construction of a model? I know of at least two other completed railmotors - one I saw a couple of years ago running on a layout (in lake livery) and another (in P4 chocolate & cream) was for sale at ExpoEM last year. I took some photos of the one for sale to help me and will come to them when I get the steps done.

This is clearly a challenging kit and one which already people have admitted to being shy of. Let's see if we can encourage those keepers of kits to take the plunge! (Are you reading this, Dave K?)

David

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David B
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Re: GWR Railmotor

Postby David B » Sun May 29, 2011 7:31 pm

Having cleared commitments elsewhere (decorating!), I have managed to tackle the footsteps.

Here is the problem. This model was on sale at Expo EM last year. I took a few photos to help me construct my kit.
truss_rod_fault_8202.jpg
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The piece of brass from which the steps hang will be fixed to the underside of the floor. The uprights are too long and have been carefully shortened. The width of the pieces make it necessary to use fine pins & wire.
step mods.jpg
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The brass plate at the top is a bit wonky because the holes that were already in it were on the large side. The temporary pin holds the step assembly together but will be replaced by the handrail which goes up each side of the door.

The steps in situ. They are articulated at the moment as this makes it easier to fit them but I shall fix them with a touch of the hot iron when I am satisfied with their positioning. They flop everywhere but are surprisingly robust and will take a fair amount of manipulation. When fixed, they will be straighter. (There is a bit of lens distortion on the photo.)
steps_in_situ_2836.jpg
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The flat bar truss rod has to be twisted through 90o and on the side of the vacuum cylinders, inserted behind the V hangers as well as through the steps. I made the queen posts from .7 wire with a brass tube sleeve 6mm (scale 18") long which ensures the truss rods are parallel to the solebar. I couldn't find any queen posts with the kit, so they are either lost or weren't there in the first place. There is cleaning up and some filling to do around the door.

David

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David B
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Re: GWR Railmotor

Postby David B » Sat Aug 04, 2012 7:53 am

It has been a while since anything went on this thread and limited progress has been made.

Does anyone know when the steps that hang off the buffer beams and go under the buffers were added? They were not on the rail motors when built but appear on photos from the early 1920s. As I am modelling the period before this, the 19 teens, the question is pertinent.

If anyone can shed light, I shall be grateful.

David

step_4893.jpg
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Captain Kernow
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Re: GWR Railmotor

Postby Captain Kernow » Mon Nov 19, 2012 3:42 pm

Sorry to hi-jack David's thread on his lovely model, but here's some footage I took on the real thing yesterday, as the 0920 ex-Looe ascends the bank from Coombe Jct up to Liskeard. All in all, a fantastic and magical day spent on and with the Great Western Society/West Coast Railways boys and their wonderful machine:

http://www.youtube.com/watch?v=uNTxWaGj ... e=youtu.be
Tim M
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Tim V
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Re: GWR Railmotor

Postby Tim V » Mon Nov 19, 2012 5:18 pm

Shocking, you of all people Captain should have read the sign about not leaning out of the window.....
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