Steaming for beginners

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1 - setting the scene

The level of interest in garden railways in Southport Model railway Society seems to be slowly rising, with four members currently owning live steam locomotives and garden railways to run them on, in various stages of completion. A couple of others are showing more than a passing degree of interest. I thought it would be timely to describe something of what this branch of the hobby is about.

First of all, scales and gauges (it can only get easier after this). Live steam comes in two main flavours, 16mm and G-scale. The former is approximately (a frequently-used adjective in this context) 1:19 in scale, making it four times the size of 00, and a mere sixty-four times the mass. Trying to show off by lifting a loco one-handed is therefore fraught with hazard.

Running on 32mm gauge track - think coarse-scale 0 gauge for an approximate (that word again) comparison - gives a representation of 2ft gauge in the real world. Hence most of these locos are either prototypes of, or freelance derivations of, Ffestiniog, Lynton and Barnstaple or similar narrow-gauge motive power. Quarry Hunslets and other industrial engines are also popular models.

On 45mm track the 16mm representation approaches 3ft gauge. Modeller's licence can be applied to allow similar locos to run as for 32mm, the main practical advantage being steadier and more secure running, due to the wider footprint. The purist can however indulge in near-scale modelling of Manx or Irish railways with a certain degree of smugness. Models with wheels inside the frames are generally gauge-adjustable with the help of a small (and easily mislaid) Allen key. Outside-frame locos are factory-built to a particular gauge, although in some cases the customer can choose which one when ordering.

Now for G-scale for which I will be mercifully brief. G-scale can vary from anywhere between 1:22 and 1:29, depending on manufacturer. It runs on 45mm track and most of it is electrically-powered using rail pick-ups. The amount of live-steam available in the UK is very limited. However just to add a little spice, some 45mm gauge models of mainline steam locos are on offer, typically to a scale of 1:32. These are normally referred to as Gauge 1 models, although convention permits virtually anything running on 45mm track to be addressed as Gauge 1. Another piece of modeller's licence practised by some suppliers is to pitch their loco sizes somewhere between 32mm and G-scale, to appeal to both segments of the market. Such are the forces of capitalism.

A frequent complaint levelled at live-steam modelling is the cost of getting started. Whilst it is easy to spend well into four figures to equip oneself with loco, rolling stock and track, it is possible to start in a much more modest way, particularly by dipping into the flourishing second-hand market. Many have started with a small battery-powered diesel kit, a couple of scratch-built wagons and a circle of Mamod track, and built up from there. Indeed when you ask an experienced 00 modeller to tot up the value of all their stock, the cash register digits can roll over alarmingly quickly. And none of it STEAMS….

Mention of kits and scratch-building brings another factor into play. The many-thumbed amongst us may well despair of ever making a decent fist of a 4mm scale kit. By contrast, in 16mm the problem gets smaller as the pieces get bigger. For models of relatively simple wagons for example, it can be little more than basic carpentry. If you can cut scrap wood with a razor saw in a more-or-less straight line then all you need to build a slate wagon are wheels and axle-boxes, for less than a fiver. Any imperfections can be assigned to natural variation in build design or to weathering, or both.

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2 - getting under way

OK, we have our live-steam loco sitting on the bench, be it budget manual Mamod or top-end radio Roundhouse. A first step is to ensure mechanical stability. A loco on blocks can rev up with some alacrity, and grabbing hold of a hot, heavy loco to prevent an unscheduled departure at speed across the man-shed is not to be recommended. Ideally one has a waist-high section of the running track for lighting-up, but such luxuries are not always readily accommodated on the average garden railway. Another first step, if such a thing is possible without distorting the space-time continuum, is to check that any radio-controlled elements actually respond to the lever of command. Having to shut down a boiling boiler because the receiver batteries are flat is definitely not conducive to relaxing steaming. Been there, got the safety valve exhaust up the nose.

According to the ancients four elements are the basis of all life: earth, air, fire and water. With the efficiency gained over millenia live-steam modellers have pared this down to three: fire, oil and water. For most of us the fire is fuelled by butane, in convenient canisters made for the camping stove market. Methylated spirit firing is rarely found on modern locos, although it has a loyal following amongst some 16millers, and not just for drinking if all else fails. And coal-firing is becoming increasingly popular, as a means of achieving the ultimate live steam experience, and hang the expense.

But we will go with the majority, and start by firing the beast with gas. This involves pressing the canister nozzle, with optional extension tube, onto the nozzle of the gas tank, first making sure the gas valve feeding the burner is closed. A hissing sound denotes expulsion of air from the tank as the gas enters, with a hint of butane fragrance as a little of it comes back out with the air. When a lot of it comes out, usually in liquid form, one can safely assume the tank is full. Prompt removal of the canister is advised, to minimise the size of the gas cloud drifting downwind across the bench. Did I mention no smoking is recommended? Whilst the butane charge settles down and sorts out its temperature-dependent phase equilibrium interface thingy, we can do some lubrication. This involves two types of oil with very different and very specialised technical specifications: thin stuff and thick stuff.

The thin stuff is a fairly conventional light machine oil applied sparingly to all external moving parts, of which there can be many. The thick stuff is destined for inside the cylinders, and gets there from its storage pot in the cab with the help of a bleed-pipe off the boiler. The pot is drained of condensate and refilled before each run, taking care to screw the cap back on properly. Failure to do so results in a hot sulphurous emulsion being spattered all over shiny paintwork and polished brass, and burnt fingers whilst trying to remedy the situation. Normally you only do this once, although I have managed to repeat the experience with hardly any effort.

The final act in the trilogy of preparation is to fill the boiler with water, normally by squirting it in via the safety valve tapping. Now there is endless discussion amongst model steamologists as to what quality of water should be used. Some say anything out of the tap in a soft-water area is OK. Others swear by double-filtered rainwater. Yet more prefer to make their own weapons-grade water by burning high-purity hydrogen in an atmosphere of medical oxygen - sorry I made that one up, but you get the picture. The aim is always the same, to keep out not only dirt but also the dreaded carbonates, sulphates and chlorides, which can encrust the inside of small-bore pipework and starve your cylinders of steam. For some reason deionised water is disparaged as being just too artificial and unnatural, rather like the magnificent newly-restored Flying Scotsman shunting a rake of scruffy coal wagons.

At this stage any audience you may have will start to perk up and pay attention, and pretend there were not at all bored by the process so far. For in your non-dominant hand (right in my case) you will be brandishing a source of ignition. A gas lighter is the tool of choice, although for reasons of economy a match can be substituted, at some risk to the hairs on the back of your hand. The other hand takes a firm grip of the gas valve, and with a flick of both wrists you simultaneously open the valve and apply the flame to chimney or open smokebox door, depending on loco selected.

If the laws of physics are pleased to be satisfied with your efforts, there will be a quiet pop and a gentle roar as the gas ignites and settles contently on top of the burner. However, if Murphy's law is in the ascendency, either nothing will happen or burning gas will erupt from the smokebox with all the enthusiasm of a junior flamethrower, complete with sonic boom. You are not dismayed however, and deftly shut the gas valve, relight the lighter and try again.

This time (probably) all is well, and the admiring crowd breathe out again. All too soon, as you sip tea and chat knowledgeably about the merits of multi-tubed dual-fuel ceramic gas burners, there are signs of activity on the loco front. The pressure gauge is twitching, the safety valve is bubbling and the wheels are making strange jerky movements. The realisation that the moment of truth has come is accompanied by either a frisson of excitement or a strange feeling of impending doom. Now this hot, smelly dripping thing has to be driven, in a controlled and efficient fashion. There is no going back.

Southport Model Engineering Club

3 - chasing the (fiery) dragon

First a recap, for those who have expunged their memory of the first two parts of this saga. Your loco of choice is spitting steam and hot water from several apertures, the track has been cleared of recalcitrant flora and renegade fauna, and the garden gnome has suddenly sprouted a green flag from under his armpit. You are good to go, whether you want to or not.

The first task is to get the loco down onto the track. One manufacturer thoughtfully provides a pair of delicate cotton gloves for this purpose, although industrial-strength hand protection is better suited to any prolonged handling. The golden rule is to grip by the buffer-beams and ignore any emission of fluid which movement only seems to exacerbate. All is normal and expected, honest. Apart from the safety valve suddenly ejecting vapour at 40psi into your unprotected face. Make that a firm grip on the buffer beams.

With practice, lowering the engine straight onto the rails in the correct position can be a symphony of smooth, resolute movement. Getting that practice may involve muttering rude words of exasperation as the wheels refuse to line up with the track, and you realise you have forgotten to reset the wheel gauge after a recent visit to a 45mm line. For a manually-controlled loco the next guess is how far to open the regulator. Too much and the engine sets off at great speed, to derail at the first bend and bury itself nose-first into a rose bush of few flowers but many sharp thorns. Too little and the loco goes nowhere, until you move the regulator a little more and it sets off at great speed, etc.

Fortunately experience is a great teacher, and sooner or later the optimum position is identified and the loco sets off at a modest pace, just as you realise it needs to be attached to a train. Attaching said train is a simple matter of either pushing together a well-oiled set of scale chopper couplings, or perhaps just hanging a bit of sink chain over two hooks. Either can be more fiddly than they have a right to, with the loco all the while sitting impatiently nearby, blowing off steam at increasingly frequent intervals. Eventually all is ready, and with the regulator cunningly adjusted for the extra load, the whole unit trundles gently off into the near-distance.

Perhaps surprisingly, manual locos can be quite tolerant of curves and gradients, if necessary pausing for a blow-up before uphill sections and running downhill with only modest acceleration. Excessive variation in alignment can sometimes be a problem, and occasionally runaways have to be curbed with a rapid dash across the lawn to intercept the offending item before disaster ensues. However with well-designed trackwork and a skilful driver, the scene can be one of bucolic charm and peaceful progress, across a sunlit vista of well-harmonised garden railway and railway garden. No knobs to twiddle or batteries to go flat. All that is needed is a deckchair and cold drink of choice to enjoy the scene, all the while wishing the neighbour's dratted children would stop making so much infernal noise.

Until the gas runs out of course. This may typically be after about 25 minutes, hopefully accompanied by at least 26 minutes' worth of water consumption. The better-equipped machines have provision for water top-up on the go, so it is possible to keep going almost indefinitely. In practice inertia eventually sets in, particularly in warm weather, and the attractions of deckchair and drink of choice becomes irresistible. Everything slows down, steam is replaced by low-maintenance battery-powered diesel and thoughts of barbecue begin to surface. And then it starts to rain.

Finally, one must examine the added benefits of radio control. The price of such equipment has come down as its sophistication has gone up, so there is little to prevent any engine being so fitted, if one desires. Getting regulator and reverser to move in prototypical manner can involve some nifty work with connecting rods and cranks to get the angles and torque levels right. However the end result can be a loco which is smoothly controllable in both directions from the other end of the garden. Curves and gradients are reduced to mere adjustments of the left-hand transmitter lever, whilst judicious use of the right-hand control allows shunting to be undertaken with relative ease. The purist may claim this removes some of the essential aura surrounding garden railways, making it too predictable, even a touch tame. However for the rest of us it frees up some cognitive capacity to worry about the real issues, such as whether one's train can reach the passing loop before the one coming the other way gets there. Or whether there will be muffins for tea.

First published in the magazine of the Association of 16mm Narrow Gauge Modellers

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