I know nothing about the energy requirements of a model live steam engine, but your thought of using lead acid cells to provide 10 amps at 24 volts and discharging at the 10hr rate would mean a rather large battery pack to squirrel away behind a 2 1/2" locomotive, well judging by the one's that I have seen. I would suggest that LiPo cells are a much more practical idea at this scale, that is, if electrically raised steam is a practical proposition. For 24v you would require a 6S pack of suitable capacity, but rather than building a tubular boiler, would it not be better to construct a flash steam generator to minimize the stored energy? An interesting project no less.

Trevor

Graeme How many cylinders do you have ? If two then only a 4 minute run

Roy

This thread reminds me of an idea I heard of many years ago. At the time I did some work for Mamod when they were based in Slough. The chap in charge of the model workshop was toying with the idea of "firing" the stationary engines electrically, using Diesel engine warming plugs as heating elements! I don't know if he ever tried it.

Yes Maurice, diesel induction manifold heater plugs work well as mini immersion heaters, though I used them for heating oil rather than spraying/dripping water on them in a closed volume to generate steam under pressure, but they should be okay as they get pretty arduous use in old tractor manifolds, especially in winter cranking up worn out engines. Some info here Graeme

https://www.picoauto.com/library/automotive-guided-tests/glow-plugs/#agt3

Trevor.

Electricity to generate steam is not a new concept, the issue as already been mentioned to shoehorn some battery packs into the loco or tender, you will still require the tender for water but I think that the flash steam boiler may be the better way to proceed. It has been used in model boats before and releases a huge amount of power.

On the other end of the scale wasn't there a steam turbine loco trialed by one of the big four? Unfortunately this was a bit of a flop, but on a smaller scale, combined with the flash boiler and electric power could be an interesting model engineering concept. (Though the more learned amongst you all will no doubt rubbish thia idea for the same reason as the full scale turbine engine was a flop. Electrically generated steam turbine loco……. will be interested to see what if anything comes of this conversion discussed. Unfortunately the engineers of the hayday of steam had years to perfect the design, from the Rocket to engines like Mallard and everything in between, even fireless steam engines. All proving more efficient in their steam making capabilities.

Good luck and I'll be reading replies to this thread.

LMSR Turbomotive was anything but a flop, it was a success, but didn't fit in with the policy of the BR standard designs. It was converted to conventional when the turbines wore out.

on the subject of electric heated boilers, A medium size 5"g loco might have a 17 sq.in grate and would develop about 16kW heat input (35lbsof coal/sqft/hr). The efficiency is about 70% so for electric heating you'd need 11kW. A Dyak is a lot smaller, say 3kW, but still a lot of battery power. If you wanted to run for 1/2 hour with 12v battery you'd need 125Ah of battery, which is a lot

The electrically heated locomotives used in Switzerland could operate for a limited time as fireless locomotives on non-electrified tracks leaving me to wonder whether it might be possible to use the boiler for energy storage instead of batteries. I wonder what the running time would be for a small-scale fireless locomotive where the water is heated electrically whilst stationary rather than fed in from a separate boiler?

Without the need for a blastpipe the boiler (or accumulator) could be extended to the front of the smokebox, increasing its storage capacity. Power and water would come from a trackside plant (at its simplest a power supply, a tank and a hand pump) which could be mains, battery or generator powered, so there would be no need for the locomotive to have a tender, injectors, gauge glass or even an on board feed pump. A suitable heating element would be required, either one that could withstand the pressure, or less efficiently a heating ribbon between the boiler and its insulating jacket, which would simplify the boiler construction and perhaps make it easier to achieve the higher pressure necessary to maximise energy storage.

Brian

Certainly used similar in full size, simply a steam storage vessel which is topped up from the factory steam main. The engine just uses the stored energy, no fire no water just energy storage. I doubt whether this would work on a smaller scale, too many losses and not enough storage.

Seen in the Budapest Railway History Museum ( Magyar Vasúttörténeti Park ) a couple of years ago this fireless 0-4-0 tank loco 91,001 (UIC B-f2t) is definitely different. Technically it probably isn’t a tank engine as it has no tank or firebox, just a large steam receiver. Designed for working in hazardous environments, the receiver was just filled from the factory steam main as required. Built by Lokomotivfabrik Krauss & Co. of Linz am Donau, Austria in 1915.

John

Edit: Typo

Edited By Journeyman on 20/03/2018 09:44:08

Instead of going all-out electric which would, let's face it, be the most efficient – How about running a 12V compressor and use the boiler as a compressed air tank?

Edited By Jon Gibbs on 20/03/2018 09:57:47

My earlier post refers.