Something a bit unusual - a steam railmotor

[Snailrail]

Hi everybody,

It's a long time since I posted anything on here though I do come here and look around quite often. Despite an abundance of time over the last year I must admit I've found it hard sometimes to raise the motivation for modelling though, to be fair, I did achieve quite a bit outside working on the line back in the first lockdown in the spring when the weather was good.

I've had this project in mind for quite a long time but despite hours of thought and inactivity I couldn't decide how best to achieve it. Eventually I came up with something I thought might work and started planning around three years ago. I always intended to write it up on here for the amusement of others but decided not to do it in real time for two reasons :

1) My modelling tends to consist of brief periods of furious activity interspersed with long periods of gathering dust and I figured that doing it in real time would result in you losing the will to live between instalments.

2) I wanted to get to a sufficiently advanced stage of construction before sharing it so that I could be reasonably sure it would actually work and look ok. This would hopefully avoid the embarrassment of getting months down the line and deciding I would have to scrap it and think again !

So with time on my hands I have decided that now is the time. I will post the story so far in a series if irregular instalments in the hope that this will encourage me to get on with it and make progress. Hopefully by the time the story catches up with construction I can avoid situation 1) above !

So what is it ? Not going to tell you. As a little tease this is part of the inspiration. I will reveal all next time

[Andrew]

Intriguing! I look forward to hearing more...

[ge_rik]

Ooooh! I do love a mystery.

Rik

[Peter Butler]

'Unusual' is my absolute favourite.

[Snailrail]

Ok' well it's not that unusual in its wider application but I have never seen a model of exactly what I had in mind although of course it is entirely possible that someone, somewhere has built something similar. There are many very fine railcars out there but they seem to be nearly all electrically powered models of petrol / diesel powered prototypes. I wanted to build a steam railmotor.

I have seen a very nice model of a steam railmotor of the type which has a small conventional loco with an attached coach. I did consider this at one time but the problem seemed to be finding a small enough loco. I bought an Accucraft Ragleth power unit with this in mind but it was much too big and I ended up building a brass Manning Wardle style body to make a Lynton and Barnstaple might-have-been.

I wanted to build a fully enclosed type of vehicle and the only model of this type I have seen is the well known Locomotion railcar. I always felt that these looked rather toy like and I didn't like the single fixed front axle arrangement. Like half a bogie coach cut and shut with half a four wheeler ! I know it was obviously done for simplicity of engineering but frankly it offended me ! It can't be ideal on lines with sharp curves either.

I wanted to build a sort of upgraded version, a bit more prototypically correct and aesthetically pleasing. I had two "must-haves" to start with.
It had to have a vertical boiler.
I have always liked the well known LSWR/SR "gate stock" coaches which were rebuilt from the early LSWR railmotors which were never very successful. I like the gated centre vestibule and wanted to incorporate that into my vehicle.

I then considered other factors in the design. For ease of construction it should have -

an articulated body ( more work in the body but easier mechanically )
smooth flat sides
square corners
flat ends
simple arc roof

So the vehicle I am building has -

a rigid body
curved sides with tumblehome
heavy panelling
rounded corners
bowed ends
elliptical roof



So, time to draw out something full size on paper, expecting this to be the first of many before I got it right. Unbelievably I was completely satisfied with the look of my first draft and, with only a couple of minor adjustments, that is what I am building. This is what I came up with



Next time before I start on body construction I will talk a bit about the engine unit, still only half built, as that dictated certain aspects of the body design.

[ge_rik]

Sounds intriguing, Brian. Looking forward to the next installment.

Rik

[Soar Valley Light]

Sounds intriguing, Brian. Looking forward to the next installment.

Rik

Me too! I think steam powered railmotors are fascinating

SVLR Andrew

[invicta280]

I will be watching with interest. I fancy building something similar maybe based around a mamod VB unit.
The centre vestibule gatestock are attractive vehicles. Got a drawing of one in an old magazine.
Will you be finishing yours in salmon pink/chocolate brown?

[Andrew]

Nice!

That's a lovely design, I'd never have predicted that a classic railmotor design would combine so beautifully with "gate stock", but you've nailed it...

Looking forward to future updates...

Andrew.

[Snailrail]

Will you be finishing yours in salmon pink/chocolate brown?

The LSWR colour scheme is very attractive but no. The body is already virtually finished and painted and I'm pretty pleased with it but you'll have to wait a little while till I get to that.

I meant to say when talking about the design that I have a small paperback book called British Railcars by David Jenkinson and Barry Lane. This contains a lot of interesting photos of all types of railcar, some very attractive, some hideously ugly ! There are a couple in there, one built for the Barry Railway and one for the Great Central, which also has the gated vestibule feature. Both of these influenced my design. It is no accident too that as the story goes on you may pick up on similarities with the restored Great Western railmotor - on a much smaller scale !

[Old Man Aaron]

Watching this with great interest..

[Snailrail]

Hello again, episode 3

As I said last time I will talk about the engine unit this time. Although it is only part built the basic unit is complete and is obviously what had to be considered from the start as the body is necessarily designed around it. The position and plumbing of the ancillary parts still have to be decided but there will be plenty of space compared to the cab of the average 16mm loco so shouldn't be too difficult.

As mentioned in the first episode, it was seeing pictures of Roy Wood's little deWinton locos which got me thinking. I started wondering if I could use one as it came out of the box, or with a little modification, as a basis for my project. I even bought one to test the idea. It might have worked in an articulated design but it was soon clear the idea was a non starter in a rigid body. It was useful however to have the deWinton to obtain dimensions of the boiler particularly to help with body design. I was aware from the start that the boiler is quite tall and I would have to do everything I could to keep the roof line as low as possible or the vehicle would end up looking too big.

For the sake of looking as authentic as possible I also really wanted the cylinders below the floor in the conventional position. I then realised that Roy also produces a small conventional loco called Janet for which he will supply just the chassis, complete and ready to go. So that seemed to be the answer - a deWinton boiler fixed in the body mounted on a Janet chassis as a sort of power bogie. This would of course require some sort of flexible steam pipes - more of that later. So I ordered the boiler /chassis from Roy plus a few bits from Roundhouse and other places and ended up with a box of bits.



The chassis has already had the rear section removed as not required. The gas tank was bought second hand on ebay but will probably be replaced with a more conventional one. Still not sure if I will bother trying to fit the whistle. I was going to fit the chuff pipe but that would require another hole in the roof which would spoil the look so I am going to do without the chuff and run the exhaust into the chimney. The flexible steam pipes were made for me by the kind people at Roundhouse but are unfortunately too stiff for the job they will have to do. I did buy some more flexible silicone tubing which might do the job. If anyone can suggest where I can get some very flexible tubing to fit 1/8" tube and suitable for steam, I'd be grateful.

A bit more after lunch . . . .

[Snailrail]

OK, to finish up the power unit so far . . . .

The boiler is mounted directly on the brass plate which will sit on top of the floor panel. This is cut out in the boiler compartment to allow the chassis to go through from the top. Speaking of the chassis, I meant to say that I am not over keen on the waggly cylinders but all the chassis available from the likes of Roundhouse with proper cylinders and valve gear are considerably larger and would have resulted in a vehicle which looked much too high off the ground.

In mounting the chassis on the baseplate there were two considerations. As there was going to be limited space between the side frames for the bogie to swivel there was going to be an optimum point which would allow the greatest angular movement, i.e. allow the vehicle to traverse the smallest radius curve. This point proved to be just in front of the front axle. This is obviously not the ideal point to carry the weight. That should be around the mid-point of the wheelbase. How to get round this ? Use both !

I made a brass bracket to fit between the frames which would also mount the reversing servo (more in a moment). I soldered a brass pin into the bracket at the ideal pivot point. This is just a pivot and carries no weight. I then soldered a brass rod across the top at the wheelbase mid-point which carries the weight and allows pivoting in a vertical plane. This is a sliding joint - a bit like a Mallet !



I wanted to incorporate R/C reversing which looked a bit awkward to do with the little lever on the front. So I turned the reversing block around so the steam pipes will come out of the front and curve back and the reversing lever is on the back. The servo was then fitted between the frames as shown in line with the reversing lever driving it directly via a small slotted brass lever. Seems to work !



And this is the whole assembly. The bogie is only held on by the pivot pin pushed through the hole in the base plate and secured with a small R clip. This is as far as I've got with it - just hope I can sort out the plumbing and the steam pipes now !



Next time body construction begins.

[SimonWood]

This is an inspiring build! And explained and illustrated with great clarity.

Following along with interest.

[Snailrail]

Thank you Simon.

Now on to the body construction. The body consists of two separate boxes either side of the central vestibule, requiring four separate parts for the sides. These are the parts for the sides of the rear section, three layers, the centre one 1.5mm ply for most of the strength, the layers on either side 0.8mm ply. You will see that the window openings in the centre layer are open to the top. The window apertures in the front and back layers are slightly smaller to form a frame to retain the glazing which can be simply slid into place from the top when everything else is complete. This will become clearer later. All the parts were cut out by hand using drill, Stanley knife and much (very careful !) filing and sanding.



The parts for the front section are basically the same but have two small extra layers to give the impression of an internally sliding door to the engine compartment.



Unfortunately I didn't take any photos of the actual assembly of the sides but I found a piece of scrap hardwood and planed and sanded one edge down to form the required profile of the curved tumblehome of the sides. The centre and rear layers were then glued together while being clamped to the hardwood former. Once the glue was thoroughly hard the outer panelling layer was glued on in the same way. A bit nerve wracking trying to make sure it was all lined up perfectly before being clamped together ! Anyway it seemed to work very well and I was pleased with the result. I also added some thin outer frames to all the windows.

[philipy]

Wow! That is a work of art, not just a steam railmotor body!

[Peter Butler]

Just beautiful, superbly designed and cut, it will look superb. My only reservation is that I find it better to paint overlays before final assembly for a crisper finish.

[Andrew]

it seemed to work very well and I was pleased with the result.

I should think so, it's fantastic! I've always avoided scratchbuilding carriages with curved windows/panelling and tumblehomes, but you've made a beautiful job of it - I very much look forward to the final outcome...

All the best,

Andrew.

[Snailrail]

Thank you for the kind comments.

My only reservation is that I find it better to paint overlays before final assembly for a crisper finish.

I take your point Peter if you're thinking in terms of contrasting colours for the panels but I have done the whole body one colour with lining round the panels so it's not really an issue. Look at the restored GWR railmotor 93 for an idea - this was one of my main inspirations, including the colour scheme.

[-steves-]

Also following with interest, however one thing does concern me, that plastic bodied, plastic geared servo that close to all that heat

Other than that, looking great so far