As no one has responded yet here is a first pass set of thoughts.

1/ Can I assume by Class 52 the Western Warship? If so this is actually a diesel hydraulic not a diesel electric…. Just a wee starter there.

2/ As a regular inhabitant of the ” Rabbit hole of spiralling complexity ” the thought of modern traction in 3 1/2″ gage fills me with dread to build a potentially very complex locomotive in such a small scale. Not impossible, but ‘potentially’ very difficult. I think 5″ is usually the starting point for this.

3/ The type of power system needs VERY careful thought and there are a range of options. These are….

a) Pure electric drive with batteries, controller and traction motors. Then usually a sound system to make it sound realistic.

b) An internal combustion engine – In the case of the Class 52 Warship coupled to a fluid torque converter driving the bogies through a reduction gearbox and Carden – shafts. Definitely the next stage up. The issue is the prime mover here, a commercially built unit, for this scale very small and possibly not robust enough for rail service. OR build your own, next level up again…. Thus depends on ones skill level…

So, designs available that I know about.

3 1/2″ Gauge 0-6-0 names “1831” by Edgar Westbury utilising a 2 cylinder IC engine.

5″ Gauge Hymec by Roy Amesbury –  was described in ME commencing volume 160 no. 3827 – June 1988 – A v8 petrol with hydraulic transmission, so prototypical arrangement but not to scale internally. He went a fair bit down the rabbit hole but not too far that he met the white rabbit…..

Then there is a 52 in 5″ gauge – I think there may be more than one – but this one from Phoenix is typical of the ‘basic’ battery powered Diesel outline models.

https://phoenixlocos.com/products/model-locos/class-52-western/

Usual disclaimer, I have no connection or knowledge on the particular model.

In modern traction land it is ‘relatively’ easy to build an electric powered outline model. The minute one tries to cross into the more scale realm the complexity goes up by the exponential function the further into the rabbit hole one goes.

I did some thought concepts for a 7 1/4″ Ukranian M62 and it was scary how quickly the complexity escalated, I ran back out that rabbit hole very quickly.

I did a small 5″ ‘electric’ diesel many years ago ( Brush Bear Peacock D2999 ) and it was reasonably OK but NOT I.C.

If I was doing this in the future I would probably only look at pure electric traction and avoid Diesel…..

But it depends on your goal and level of skill.

Hope that minor ramble assists…..

Best regards.

Some years ago, a member of the Hereford SME (UK) was making an ICE powered Warship or Western, actually making his own torque converters; in 5″ gauge from memory The loco was well advanced, when exhibited.

I never saw the completed loco, so he either moved away, gave up, or passed on.

Howard

I’d couple the axles on each bogie (tooth belt or chain) then have a bevel box on an axle with motor mounted longitudinall on main frame.

A vee4 variant of the Sun so it will start at any crank angle with a mechanical drive could well be easier! Something on the lines of a Heisler but with chain coupled axles.

Dont the two bevel gears driving the eccentrics clash ( one omitted for clarity!)

On 14 May 2025 at 07:22 JasonB Said:

I only cobbled together a few bits from the two cylinder parts that I have drawn up. Hence no crankcase it would need a couple of details like the gears and a different crank sorting out. You could possibly mount two bevel gears “back to back” on the crankshaft and stagger the vertical shafts to match the cylinder offset.

Something like this, what do you propose for the V4 Sun?

If you wanted to stick with internal combustion then a new

On 14 May 2025 at 07:22 JasonB Said:

…… bevel gears “back to back” on the crankshaft and stagger the vertical shafts to match the cylinder offset.

Something like this, what do you propose for the V4 Sun?……

 

Thats when I gave up daydreaming, although something like a pair of semi rotary valves (like a Corliss) driven from eccentrics on the crankshaft might work. Or a piston valve for each cylinder with the valves at the ends and an eccentric or cam at each end, like 4 Spartan engines.