AEC Railcar Project

[Mol_PMB]

I have a long-term plan to develop a model of an AEC Railcar, primarily etched brass with 3D printed components.

Others have expressed interest in contributing, including @Rob R and @lucas, so I thought I'd start a thread for the project rather than have it scattered around other threads. 

As part of my research for my talk on AEC Railcars this autumn, I have been gathering photos of them and I now have an index of about 640 images. Once I've tidied that up a bit, I'll post it here. 

I've also been gathering drawings from various sources, none are perfect but I think that between them I can develop a reasonably accurate shape. Here I've just pasted them all onto a drawing board. They're not even all to the same scale yet, bear with me (and sadly I don't have the originals to smooth out those folds).

If only we had the bodywork jigs and tools that Park Royal offered to Bulleid in September 1954...

This is a long-term project, I'll potter away on it from time to time. The first thing I want to do is create an accurate 4mm scale drawing, which is quite a task in itself.

 

[leslie10646]

Hi Paul

I assume that you've got Richard McLachlan's scans of the IRRS Archive set of the drawings?

You realise that now that you have announced your intentions that IRM will announce theirs for delivery RTR, with sound, lights, passengers and ten liveries by Christmas (although not saying which year).

[Mol_PMB]

8 minutes ago, leslie10646 said:

Hi Paul

I assume that you've got Richard McLachlan's scans of the IRRS Archive set of the drawings?

You realise that now that you have announced your intentions that IRM will announce theirs for delivery RTR, with sound, lights, passengers and ten liveries by Christmas (although not saying which year).

Hi Leslie,

I do have Richard's scans, but there aren't many good ones featuring the railcars - mostly livery diagrams of the front ends. Unless I'm missing something?

If my work makes IRM produce a model, then great! I think it's unlikely in the present climate, but we'll see.

 

[Mol_PMB]

The drawing with the most comprehensive dimensions is a photo of a rather rumpled original. It is pleasing that drawing up cross-sections and plans based on the quoted dimensions gives something that can be overlaid over other drawings that are flat, but less well dimensioned. This starts to give some confidence in what I'm drawing (in red).

A long way to go yet - the proof of the pudding will be when we can produce a 3D 'face' that looks right.

[Bullet_Wanderer]

Very funny timing! I've been modelling an AEC railcar in Blender, doing it by eye as I couldn't find any good scans of 'em, and here you have a ton! Hope you don't mind if I borrow the scans to rework my model

You're right about the 'face' of it as that's been the most finicky part despite being relatively simple. Looking forward to seeing how this project progresses!

[Mol_PMB]

2 minutes ago, Bullet_Wanderer said:

Very funny timing! I've been modelling an AEC railcar in Blender, doing it by eye as I couldn't find any good scans of 'em, and here you have a ton! Hope you don't mind if I borrow the scans to rework my model

You're right about the 'face' of it as that's been the most finicky part despite being relatively simple. Looking forward to seeing how this project progresses!

Welcome to the team! 

[popeye]

5 hours ago, Mol_PMB said:

I have a long-term plan to develop a model of an AEC Railcar, primarily etched brass with 3D printed components.

Others have expressed interest in contributing, including @Rob R and @lucas, so I thought I'd start a thread for the project rather than have it scattered around other threads. 

As part of my research for my talk on AEC Railcars this autumn, I have been gathering photos of them and I now have an index of about 640 images. Once I've tidied that up a bit, I'll post it here. 

I've also been gathering drawings from various sources, none are perfect but I think that between them I can develop a reasonably accurate shape. Here I've just pasted them all onto a drawing board. They're not even all to the same scale yet, bear with me (and sadly I don't have the originals to smooth out those folds).

If only we had the bodywork jigs and tools that Park Royal offered to Bulleid in September 1954...

This is a long-term project, I'll potter away on it from time to time. The first thing I want to do is create an accurate 4mm scale drawing, which is quite a task in itself.

 

It might be easier to 3D print the whole thing Body, Roof, Floor and Bogies.

[Rob R]

3dp ends, interior, roof and underframe details with etched chassis and sides?

Limited by the size of the available printers for the roof, although it might be feasable to do two halves. 

Suck it and see..

Edited Monday at 21:43 by Rob R

[Mol_PMB]

I think etched brass has many advantages for the main construction of the chassis and bodyshell - strength, thin so that glazing isn't recessed, less likely to suffer from distortion or build lines.

But 3D printing has a major part to play no doubt, much as Rob R says above. I'd add cosmetic bogie sideframes to that list, probably overlaid on etched brass structural frames.

Etched brass is also the technology I am familiar with - if people want it 100% 3DP then someone else would need to take the lead.

 

There's a lot of work to do before we can start detailing up any parts, so please be patient.

[lucas]

I agree that etched kits always look a lot better for coach/railcar sides. A hybrid etched/3D printed kit would be my preference too.

 

Not sure what you want to do with the roof?

The front section above the cab would need to be 3D printed. The rest could be brass but it might be tricky to get the curve to match up perfectly. We could also print it and get the curve exactly the same, but that would probably have to be printed in a few sections giving a few more joins to clean up.

[Mol_PMB]

The roof (apart from the dome) could be either, and I’m considering options. 
An advantage is the very prominent gutter which allows the roof to be made a separate component without any worries about visible split lines. 
Also the roof is basically smooth apart from the vents and boiler exhaust, the seam lines are so fine it’s best not to try and model them. 

[lucas]

1 hour ago, Mol_PMB said:

Also the roof is basically smooth apart from the vents and boiler exhaust, the seam lines are so fine it’s best not to try and model them. 

I was mostly thinking of the unintended seams where brass and 3D printed parts join, but I guess it's nothing that a bit of model filler can't fix.

 

 

Also, moving the discussion about motor bogies here:

On 17/8/2026 at 1:24 PM, Mol_PMB said:

I've been looking at power bogie options too - with various possibilities including diesel power bogies, black beetle, or a custom etch using High Level parts.

36 minutes ago, Mayner said:

I ordered 21mm gauge 10' wb powered and un-powered Blackbeetles from Steam Era Models to power an AEC railcar set almost 20 years ago, nearest thing to a rtr 21mm gauge RTR chassis manufactured in Australia.

Used the bogies to complete a railcar set assembled using Worsley Works parts with a roof carved from balsa. Main draw-back was I ordered MTK/NNK AEC railcar bogie sideframes (9'6" wb) though useable and cast ends which were asymetric with a distinct squint and unusabe.

Steam Era Models Blackbeetle manufacturer may still be in business (accessed their site last week) and produce a power bogie with a 27:1 gear ratio, more realistic top speed and controlable than their standard 15:1 gear ratio. I once unsuccessfully attempted to re-gauge a OO Blackbeetle to 21mm gauge (for a diesel shunter) and damaged one of the force-fitted drive gears by reaming the bore while attempting to replace a wheelset. Impossible to Loctite a gear to an axle due to the design of the bogie, guess I could try and form a spline at the centre point of the axle. 

The High Level LongRider would've been ideal with 40 mm wheelbase, it's a shame it's not made any more.

 

I am in the process of making my own etched motorbogies for my C class build. They're designed around a Mitsumi motor with a 30:1 gear ratio (the largest gear ratio I could find for a single stage worm) which should give a nice slow top speed of ~50 scale mph.

I had already built the first set, but I miscalculated the clearance so the gears bind up pretty badly. I need to get them remade with a bit more clearance. I have attached some pictures below.

 

Some of my thoughts:

My design only works for 21mm, it's too wide for OO gauge. You would either need to have a design where the motor isn't contained within the side frames, or a teeny tiny motor.

High Level discontinued the LoRider/LongRider when their supply of Mashima motors ran out. There aren't many sources of good dual-shaft motors anymore which are required for motorbogies like these. I'm using Mitsumi motors I bought in bulk from China for cheap, but there are definitely a few duds in my batch. I spent half an afternoon testing and measuring all my motors to make sure the ones I'm using are good and well matched, but not everyone has the equipment to do that. And I have no idea about their longevity.

As far as I know Black Beetles use Mashima motors too (or at least did in the past) so if you're planning to use them it might be worth checking if they have enough supply available.

Motorbogies aren't very powerful, so for a railcar with 2 intermediate coaches you would probably need at least 2 of them. But it might be worth doing some testing through tight curves or an incline.

[Horsetan]

1 hour ago, lucas said:

...The High Level LongRider would've been ideal with 40 mm wheelbase, it's a shame it's not made any more.....

It may still be worth asking Chris if he'd be willing to sell the LongRider etch only, so that you can experiment with other motors.

I have two full LoRiders/LongRiders for my Derby Lightweights, but would probably need more etches for other purposes. 

Edited 16 hours ago by Horsetan

[DSERetc]

For anyone kit building or scratch building CIE AEC railcars, the devil is in the detail. It seems almost as soon as they were delivered CIE began making alterations.   You would need to decide how your model appeared in a particular year.   Hardly any two photos are identical in all details.  Take for example the front view.  When they arrived they had a window wiper on both windows with the motor in the top left hand corner as you look at them.  Very soon the revolving horizontal wiper was installed on the drivers side.  Above the two white marker lights were two red lights.   These were removed and the white lights raised to their positions,   Lamp irons were provided for oil tail and head lamps.  In spite of the electric lamps, oil head and tail lamps were used to comply with the rule book.  (A red tail lamp with no oil was a factor in the 1957 Dundrum accident).            As regards the side view,  as delivered, the engine valances had two screened ventilation openings in the centre, over the years more openings appeared,  then valance panels were gradually removed and not replaced.   By the time of the Push-Pulls there were no valance panels at all. GNR(I)/UTA seemed to keep using the valances.          Two points to note: as you face them, the doors have the hinges on the left and handles and grab rails on the right except for the double doors of the guard's compartment.              There were two engines mounted length-wise side by side under the floor.  The right hand one was connected by a cardan shaft to the front bogie on the right hand outside of the inner axle and the left hand engine was connected to the rear bogie on the left hand side of the inner axle.  I think there was only one driving axle on each bogie.                   As regards windows,  the first two windows of the 1st class saloon were about 2/3 the width of the other windows because the first two rows of seats faced the front glass partition behind the driver and those sitting there had a view ahead.  Also the last window of the 3rd class saloon was about 1/2 the size of the other windows as there was only a single pair of seats against the bulkhead.  The first window on the right (Starboard) side of the 3rd class was whited out as it was a toilet on the main line versions.                                I am not absolutely sure, but I think originally the engine exhaust was out the side beside the engine but due to many passenger complaints about the fumes entering the train, the exhaust was changed.

 

 

 

 

 

[mfjoc]

Keep us posted Paul

Even I might be interested to try and build an unpowered pair or four to run as a push pull set behind the new IRM re-engined C class