Hornby live steam at STEAM

Yesterday I went to Rail GWR Steam Convention 2003 at the STEAM museum Swindon - excellent. Hornby were demonstrating the new 4mm steam powered A4 model. It's quite an impressive engineering achievement, but the restrictions due to having the control of the heating of the water by varying the voltage on the track from 17V downwards rules it out for me. The maximum current is 5 Amps, which would have been deliverable from DCC, so why not go for that technology for the control? They have limited its appeal particularly in USA where DCC has really taken off. The control of the engine seems pretty good (it uses a skew wound motor, which the demonstrator thought was 3 pole, to control the input of steam to the cylinders). I thought that 2 of the attractions would be the 'authentic' steam sound but apart from the whistle this seemed virtually absent and exhaust steam from the chimney which again was only 'whispy' and unprototypical.

Although the superheater brings the steam temperature up to 280 (or was it

208?) degrees C, there seemed to be no damage to bodywork or paint as the plastic is heat resistant and stable up to 400 deg C. The operator said that he could pick it up by the bodywork after running but would not care to hold it for very long.

The mechanism protrudes into the cab which contains an unprototypical lamp which flashes red/green to indicate the status of I assume the bolier temp etc.

My conclusions are that it is an impressive achievement to get controllable live steam in 4 mm but considering its non compatibility with DC or DCC locos (yes of course you could isolate it into a siding, change your power supply and controller and use your other locos but woe betide you if you forget and put your other locos on live track, but who wants this other complication?) is not something I would want. As it requires an electric motor inside it anyway, power to the track, a dedicated controller and doesn't give 'authentic steam sound', I would prefer to spend the 500 pounds it costs on upgrading my DCC system to put digital sound in my locos.


Reply to
Alan P Dawes
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Indeed. That does seem particularly daft. Maybe I have a USA-centric view, but I can't imagine running w/o DCC. In fact, the availability of DCC is one of the key things that brought me back into the hobby. (And please, let's not start a DCC flamewar over that statement. It's just one man's opinion about what makes the hobby pleasurable.)

But, let's think for a moment.. 17V at 5A can be handled by a DCC controller, although you might need a G-scale one, or to homebrew something. But, why not do a DCC installation in this beasty? It would perhaps need two loco addresses, one for heat and one for throttle, but that's not a big issue. I think the big issue would be finding room for the decoders.

One might also be able to get by with rough voltage control of the boiler... think "full heat" for warm up, and "simmer" for running after having reached a boil. Now you could use a single H0 or N scale decoder, use the speed control directly on the throttle, and use a couple of function outputs driving a FET designed for switching power supply service on the boiler.

Who will be the first to demostrate a DCC controlled live steam A4?


Reply to
Dave Curtis

just thinking out loud, and knowing zilch about DCC, but considering the Hornby steam Mallard is made out of a special heat resistant material, and contains a boiler etc, wouldn't a DCC chip fitted internally be prone to problems due to the heat, water and oil that this particular loco produces?


Reply to

Phil: That could be avoided by a suitable remote location for the module - away from the superheater (200+C) maybe nearer the boiler (100C?) but not the same as the melting of the plastic (400C 8-) ) BUT it would take a new design of module, possibly with peltier cooling unit (more current!) and heat sink - assuming space is available It would take a link with an enterprising dcc manufacturer - perhaps one is (hopefully) in the wings, and they are both just waiting to see how the concept takes off as the basic set before launcing the Mk2/ dcc option add on version? After all, there is no point unless the orginal loco proves to be a (runaway?) success. And safer not to make any announcement of it until it available/ in batch manufacture as the loco itself is.

Reply to

In article , mutley wrote: [....]

How about in (or under) the tender?.

Reply to

Trouble is, that's where the boiler is. You could have it the guard's part of a brake third immedialelt following the tender.

Reply to
Christopher A. Lee

"Christopher A. Lee" wrote

Not Wanting to put too much of a kybosh on things, but unless as you say it goes in a coach (better as out the way of heat!) I would guess at this stage, and from the diagrams dished out free with the glossies, that there will not be any spare space to fit a chip, as I am sure even with todays technology, with what is hidden under the body will fill all available space!

Still, heres hoping! If you can, I will - If you can't it looks like a sound chip !

-- Andy Sollis Churnet Valley Model Railway Department (Remove the Standard Tank from E-mail to reply)

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Reply to
Andrew Sollis CVMRD

My feeling when I started off this thread was that by not designing in DCC from the start Hornby had 'shot themselves in the foot'.

As has been pointed out already the only 2 spaces remaining are ruled out because of the sources of high temperatures next to them (280 deg superheater and safety valve in the boiler, 100deg boiler and water overflow in the tender). Even the footplate is partly filled by mechanism- perhaps someone will design a decoder disguised as driver and fireman :-) Hornby could have included an insulated pocket for a DCC decoder eg as part of the chassis but only by including it in the original specification.

The galling thing is that they seem to have included their own 'decoder board' on the footplate which I assume decodes whatever signal they have put on the track voltage to sound the whistles and control the steam input etc (according to the Hornby demonstrator at STEAM the setting of the track voltage just controls the heating of the boiler). Thus it's not just a matter of adding a DCC decoder but also either interfacing it to provide the signals expected by the Hornby 'decoder board' or rip out the board and work out what signals need to be supplied to work the mechanism directly.

I'm beginning to wonder if Hornby designed this from scratch or whether thy bought in the design at a late stage perhaps from an 'enthusiast'.


Reply to
Alan P Dawes

Large Snip

The system was invented by Richard Hallam whose original steam Duchess was described in the April 2000 issue of B.R.M. Details can also be found at

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. Control of the original was achieved by dropping the voltage, which de-activated a relay, allowing current to flow to the motor which activates the valve mechanism. As far as I know, Hornby have not altered this method of control.

Will it be safe to operate this loco with stationary DCC equipped locos on the same track, as I understand that 17 volts DC is used? I am thinking that a track could be connected via a double-pole changeover switch to a DCC system or to the Hornby Live Steam regulator. Presumably DCC locos could be left in place, if CV 29 was set to exclude DC operation on each one but I should like someone else to try this before me!

If Hornby are seriously expecting enthusiasts (especially North American ones) to buy 2 or more live steam locos, they definitely need to make them controllable with DCC.

They have been asked by several people to do this, but will they listen?

Dave W.

Reply to
David Westerman

In article , Alan P Dawes writes

It was invented by Richard Hallam in a shed in his garden. He then sought a manufacturer to take it on and had great difficulty selling it. He wrote to Bachmann without success and eventually signed up with an inventions agency. Soon afterwards Hornby wanted to see his working model and he demonstrated it (a Black 5, I believe). This was sent out to China. They worked on simplifying it to make it commercially viable and came up with the heat resistant plastic. After two and a half years they had a marketable product.

Richard and his wife turned up at the Pickering Model Railway Show yesterday, having come for the steam gala weekend on the North Yorkshire Moors Railway, and gave me the background to it all. He was apparently at the Goodwood launch on 5th September but I did not realise who he was.

I asked about the possibility of tank engines and he confirmed that this was impossible at present with the present design but he said he is working on it.

Pat Hammond

Reply to
Pat Hammond

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