Mystery analogue sound fitted 4 wheel coach

[Adam FW]

Some time last year I bought 3 modified 4 wheel coaches , 2 complete, one in pieces and a spare chassis in a boxed group from a model fair. 2 of them were Hornby the other was on a wrenn chassis and was screwed rather than clipped together (the body also feels like it's a different material and the roof is shinier but the exteroir moulding is indentical), I don't know if this wrenn one is original as I didn't realise the Hornby 4 wheeler went back that far.

 

All 3 had been painted in a beautiful dark blue with gold lining and decals for the SDJR added, one of them had a bit more work done to it though. It felt far heavier, had pickups on the wheels, passengers added, interior lights and had been painted up with a guards/baggage compartment, the seller said it had some electronics in the back and he thought someone had attempted to motorise it, at any rate I snatched them up

 

I only have pictures of the electronic one and the wrenn one as the third is still in pieces and god knows where I've put it

 

 

 

Once back home the electronic wagon became my focus, at one end was a 5mm hole that seemed to pass along the length of the carriage, on one side was a far smaller hole and at the end was a series on tiny holes. There was no sign of any drive system and the holes seemed unnecessary for just lighting, so I had no idea what else was hiding inside, maybe it had an onboard battery to keep the lights lit when stationary. 

 

 

 

 

[Adam FW]

So I broke the glue holding the roof on to find out what was inside. I could see a buzzer amongst a lot of tightly packed electronics in the guards compartment so wondered if it was a diesel horn or steam whistle. Also the interior was far better detailed than I had expected, the windows are badly crazed so it's hard to see whats inside with the roof on

 

 

 

after a bit of a poking around I found that the tiny holes were for the speaker/buzzer, the 2 larger holes provided access to a pair of potentiometers with some tiny screw drivers but putting the coach on to powered track made no noise other than an electronic scream and the lights didn't work no matter what position the potentiometers were in.

 

 

 

Edited May 26, 2020 by Adam FW

[Adam FW]

It took a lot of cleaning and I had to re-solder one of the pickups but eventually I got the coach to work. It wasn't a whistle or horn noise. It's a full analgoue sound chuffing and hissing noise that varies with power applied.

 

 

I certainly wasn't expecting it to have a DIY analogue steam sound kit fitted but I can also see why it never took off, it's very sensitive, unreliable and needs adjusting to suit the loco, track and direction of travel. But it's quite impressive that it even works and sounds reasonable

 

If anyone knows anymore about this I'd love to hear about it, I doubt this was something someone dreamt up by themselves as a one off, maybe it was sold as a kit or was a how to guide in a magasine.

 

 

[Adam FW]

I should have included a loco in the video I posted earlier as it's a lot less sensitive with another load in the circuit but you have to fine tune it for each loco using the pair of potentiometers, I believe one adjusts the starting voltage for hissing and the other the rate of chuffing but it's incredibly sensitive, it even audibly varies (speeds up/slows down by how far away it is from the controller when pulled by a loco

 

Also as you can see despite me buying the coach as having lighting and some mystery electronics, I've never once got the lights to work but the mystery electroncis do work. Perhaps there's a hidden switch behind one of the speaker holes?

 

I'll probably add a switch of my own so that  it's not always on and to prevent it overloading on my DCC layout.

 

And if anyone's interested here's the underside of the electronic and the wrenn coach for comparison. Having done some googling I can't actually find a wrenn 4 wheel coach so maybe it is bashed together and just happens to be on a wrenn chassis that fits very well.

 

[BernardTPM]

The Hornby 4-wheel coach goes back to 1976 and never had any part in the Wrenn range; it just happens that the brake van chassis that started with Tri-ang was the same length as the ex-Hornby Dublo one Wrenn used. On the plastic chassis, the 'quick release' type couplings were around circa 1980.

[Adam FW]

26 minutes ago, BernardTPM said:

The Hornby 4-wheel coach goes back to 1976 and never had any part in the Wrenn range; it just happens that the brake van chassis that started with Tri-ang was the same length as the ex-Hornby Dublo one Wrenn used. On the plastic chassis, the 'quick release' type couplings were around circa 1980.

That’s interesting, thanks for the history lesson.

 

I guess the previous owner must have simply preferred the wrenn chassis or broke the original and replaced it with an old wrenn one that happened to fit.
 

I’m not sure if it’s just the wheel diameters but the wrenn chassis does sit lower than the Hornby one which looks a bit better to me which may also have factored into the change.

[BernardTPM]

Yes, the Hornby Dublo chassis didn't have the typically Tri-ang raised buffer height so looks a lot better proportioned. There is a more recent version of the plastic chassis, originally designed for the track cleaning version, that sits at the correct height.

They are rather nice repaints and I suspect whoever did the painting used the correct PC Models/HMRS transfers for the lettering and crests.

[russ p]

That's just jogged my memory from many years ago, I bought something similar but was 'diesel ' sound but just a load of crackling really.  I think mine was for static mounting but could be from same manufacturer.  If I remember correctly I think they were based in Norfolk somewhere but can't remember their name 

[Adam FW]

59 minutes ago, russ p said:

That's just jogged my memory from many years ago, I bought something similar but was 'diesel ' sound but just a load of crackling really.  I think mine was for static mounting but could be from same manufacturer.  If I remember correctly I think they were based in Norfolk somewhere but can't remember their name 

 

At some point I'll have to get the sound unit out of the coach and see if there's a manufacturers name on it somewhere, it appears to be on a PCB which I doubt was homemade so it makes sense to be from a small manufacturer somewhere. Getting it out is the problem, the pickup wires have been superglued in place as they were probably too long and dragged on the track, but it's had the knock-on effect of holding the circuit board in place as well.

 

Crackling and screaming was all mine did before I cleaned the connections but it still makes some horrible noises if the potentiometers aren't adjusted well. I think it's one of those things which is a neat idea and was probably great to show off when it was new as it's so unusual, but ultimately it's not very good in practice.