This article appeared in Sixteen Mill Today magazine and was written by Barry Reeves.

Helga on the SMLR.

Helga is the name that Shawe Steam Services have given to their coal fired conversion of the Roundhouse William locomotive. The first of these locomotives was built for me and frequently runs on my 32mm gauge Stanhope Market Light Railway.

The main line of this railway is an appx 45 yd circuit which is almost continuously 1:30 grades and 3ft radius curves. Such a line is demanding for any sort of locomotive and an indication of how Helga performs on this line would be a good indication of how it would perform on less taxing railways.

So what exactly is Helga? You get a four coupled chassis allied to all the bodywork and boiler sleeve of the William. Inside the boiler sleeve is the excellent coal fired boiler that John Shawe builds and which turns this loco from the normally good to the very special. Also the tender is complete with watertight tank with hand pump and plenty of room for coal on the top. She is big enough to match LGB stock without looking oversized for more conventional English 16mm scale equipment.

The four coupled chassis is necessary to get room for the firebox. The mechanical water pump sits between the frames and is driven from the rear axle. The cab controls are standard Shawe Steam Services. I do not use radio control so mine has: regulator, reverser, water gauge, blower, pressure gauge and water bypass valve.

I decided on a European look for this locomotive and opted for red frames with black cylinders and everything else. At the same time I ordered a conventional Roundhouse Billy to the same colour scheme. Roundhouse were very helpful and sent a quantity of the red paint they would use on the Billy to Shawe Steam Services so both engines were painted in the same colours.

The Stanhope Railway is run as a miniature preserved narrow gauge railway. I don't model any particular railway but try to run my somewhat eclectic collection of stock as a real railway. Thus the two terminii, Stanhope Market and Martyrs Bay are each branches off the main circuit. I treat them as being four scale miles apart which means running round the circuit seven times between leaving one and arriving at the other.

Train lengths are also determined by platform length which was itself determined by what a locomotive could comfortably haul around the circuit. The platform length at Stanhope Market is 67" (1.7m) including enough room for a 5" wide locomotive to run round. This allows trains of reasonable length.

My favourite load for Helga is a rake of 6 four wheel continental coaches. They are in fact all Playmobile and have been repainted in Roundhouse red as well as being glazed and having end doors fitted. One is a van while the remaining 5 are passengers coaches, the end one of which has guard accommodation added. The train is quite heavy as lead ballast has been added. Furthermore the excellent GRS wheels run in the plastic axle boxes without bearings so rolling resistance is much greater than with a conventional steel axle in a brass bearing.

The effect of all this is that Helga has to work hard for her living. This is what any coal fired engine needs. But I add another difficulty in that I insist on running trains to a scale speed. Helga does the scale four mile journey in 17 minutes, including one station stop, which equates to about 16 scale miles per hour.

Coal fired equipment
The basic needs for running a coal fired locomotive

Engines are steamed up at Stanhope Market which is more than 1m above ground level. Trains are stored at Martyrs Bay. We'll take a cab ride on one trip and find out exactly what Helga needs and what she can do.

Raising steam
Raising steam with the electrc blower attached.

Helga stands on the platform road at Stanhope Market with the electric blower in the chimney, half a glass of water in the boiler and a tank full of water in the tender. Three shovelfuls of wood charcoal soaked in paraffin are put into the firebox and another shovelful left ready. The electric blower isswitched on, the waiting charcoal is lit and when burning well is put into the firebox. Combustion is instant and another eight shovelfuls of charcoal go into the fire. Close the door for 10 seconds to get all this burning well, then open the door and put in as much charcoal as possible. Lastly close the door.

While the charcoal is cracking and getting everything hot we go round with the oil can and put steam oil on all bearings and every moving part of the motion. Steam oil stays where we want it even when the engine gets very hot: anything else will probably run away and not do what we want. Do nothing to the fire until steam pressure reaches about 20 psi.

When, and only when, 20 psi is reached we get busy. The steam blower is opened about 90 degrees and the electric one removed. Lay three shovelfuls of coal (anthracite beans) onto the fire, close the door and wait for pressure to build. The knack of building a fire is simply that: something which you learn. I've been running coal fired engines in 16mm since 1993 but even now I have to be careful. The art is to balance the use of blower to get the coal burning while not using too much water. Also to get a good hot fire fairly quickly without burning it all away.

Helga raises steam very very quickly: much faster than any gas or meths fired locomotive which I have encountered. On Monday 10th January 2000 the following times were taken.

Ambient Outside Temperature 3 deg. C
From cold to 20 psi…………………… 4 minutes 27 seconds
From cold to blowing off at 60 psi….. 5 minutes 30 seconds
From cold to first movement………… 6 minutes 50 seconds

From this it is clear that once 20 psi was reached the internal blower took barely one minute more to bring the boiler up to working pressure. Furthermore the one minute 20 seconds from blowing off to moving was mostly waiting for the steam to force the condensed water out from the cylinders. Helga is never pushed to clear the condensate: the regulator is opened half way and I let the steam do the rest.

The very low outside temperature probably added a minute to the time from cold to 20 psi compared to a hot summer day.

Once 60 psi is reached and the engine run forwards and backwards to clear all the condensate from the cylinders we fill the firebox and with the blower on about 45 degrees run backwards down the branch, over the viaduct then directly onto the other branch down to Martyrs Bay. By the time it has run the 50 yds the fire is burning well with the safety blowing off in typical vulgar but efficient fashion.

We couple up to the train, move the reverser into mid gear then fill the firebox with more coal: the run down from Stanhope with the blower open burnt away all the original charcoal so what we have left is a half full firebox of coal. Fill the box up until there is no more room. This sounds cavalier but the engine is very hot now and if we leave the blower on for a while there will be no problems.

So with the engine blowing off, the blower about 45 degrees on we are ready to attack 55 feet of constant 1:48. Put the engine into forward gear, open the regulator from closed (horizontal) to vertical and with just a hint of clearing condensate from the cylinders Helga moves away.

Half way up the bank pressure has dropped to 40 psi without affecting Helga's ability in any way. By the time it has reached the top of the bank pressure is back up to 60 psi and we turn the blower nearly but not quite off as the train goes round the curve, onto the viaduct and is directed onto the main line circuit.

Joining the circuit at the top Helga accelerates down the 1:30 bank, gets to the bottom and then slows as it reaches a section of reverse grade which was built in to slow trains down before the 3ft radius reversing loop. Consequently Helga goes into this loop at a steady speed which is slow enough to avoid any risk of derailment. As it goes round I close the regulator slightly and turn the blower even more not quite off .

Manual control of steam engines on the Stanhope is a matter of setting the regulator so the engine will either just get around this reversing loop or will just get up the worst of the nominally 1:30 bank. The trick is to get the load to match the ability of the locomotive and then set the regulator accordingly.

Helga climbs the bank steadily and I watch it carefully in case I need to make any more adjustment of the regulator. The loco slows down towards the top of the bank but easily pulls the train around the heavily banked curve: the regulator setting is correct.

The 7 circuits are punctuated by a stop at the half way station Denny St. John. This is actually a passing loop inside the reversing loop at the bottom of the bank. We call here on the 4th circuit.

Helga is running round very steadily without needing any attention accept for the blower. Were we to run faster Helga would be producing enough draught to keep the fire burning. But running faster looks silly as far as I'm concerned so we keep the speed down as much as possible. Slow speeds are much safer on sharp curves than the more easily attained fast speeds.

The blower is closed after two laps but by the beginning of the 4th lap pressure has dropped to below 40 psi. I open the blower to about 30 degrees and pressure can be seen to rise even as the locomotive climbs the bank. Obviously I do not stop the engine while making this adjustment.

By the time we have slowed for the junction into Denny St John the pressure is right back and the engine is blowing off again. We have a mandatory 30 seconds wait at this station. A quick glance into the firebox reveals plenty of coal so I close the door and leave well alone.

Driving the engine on the blower is entirely a result of my wanting to run slowly. Increasing the speed by 10% would keep the fire burning nicely but it just wouldn't look right to me. This is of course no criticism whatsoever of Helga or her builder. For a coal burning engine of this size to be able to run at a scale 16 mph is really most impressive. The pleasure for me of course is that I am driving the locomotive. I have every confidence in it but I am making severe demands on it and so I have to concentrate all the time.

We leave Denny with Helga blowing off. The blower is closed and the regulator opened nearly fully to get the train moving on the sharp curve and then back to its usual position for the attack on the bank. Two more laps are completed before the pressure begins to drop, so on the last that we open the blower slightly and leave it on for the climb up the branch back to Stanhope Market.

Helga brings her train into the platform at Stanhope with the safetyvalve lifting and with the water right at the bottom of the glass. We uncouple, run forward into the headshunt, move the point and then run backwards past the train. Stopping at a convenient place we put 3 shovelfuls of coal onto the fire and pump a little water into the boiler. Note that Helga has run 400 yards on a very demanding railway on one firing of coal. This run took 17 minutes. A little care is needed now to balance the water level in the boiler with using the blower while adding more coal onto the fire. That's something I can do but were I unsure I could have added more coal half way through the journey at Denny St John which would have given me a greater safety margin now at Stanhope.

Note also that we could have run this journey non stop. In fact to have done so would have been easier: the fire lasts longer when the locomotive is going rather than when using the steam blower. All the various adjustments were made without stopping the engine.

The run was accompanied by the aroma of hot oil and burning coal. The only sound was that of the exhaust and the occasional hiss of the blower. There is no way of getting closer to driving a steam locomotive in miniature than driving a coal fired version.

I hope that you enjoyed our run. We try and run the Stanhope Market Light Railway in as realistic a way as possible. Coal burning steam engines and scale speeds are two of our priorities.

And what of Helga? I think that she is wonderful. An absolute pleasure to drive and very easy to fit in with my requirements. Give her a conventional flat railway with sensible radius curves and she will pull long trains at a scale 25 mph without any need for attention at all. Refilling the firebox every 15-20 minutes, topping the tank up with water and periodically dealing with the lubricator would be all that was necessary.

So just what can Helga pull on the Stanhope? Well, the maximum train that can go round the corners and the one I test the diesel with is the 6 coach rake described and a 4 coach LGB set of 2 bogie coaches and 2 four wheelers. 10 coaches and 24 axles. Helga can pull all this up the bank and around the 3ft rad curves but she slips a lot and is obviously being strained. But give her a grade of 1:50 or less and easier curves and she would easily cope with all that and much more.

But as I've said I run the Stanhope as a railway and standard train lengths are all that loco's need to pull. Hega does this with ease and is yet another excellent coal fired conversion of a Roundhouse locomotive to come out of the Shawe Steam Services workshop.

Dropping the fire
Dropping the fire at the end of the run

© Barry Reeves
12th January 2000

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