Thermodynamic efficiency.

I am not a physicist, but these arcane thermal efficiency figures are theoretical and are regularly trotted out, mostly by IC proponents (blinding us with science?); as far as overall efficiency is concerned, a notion more easily understood, when the two technologies, steam and I.C., have been directly compared in regular service on the same job over a similar period, it's about even-steven with a small advantage in favour of steam.

To get an idea of what could be done in the 1990s with steam I suggest taking a look at Roger Waller's article For the Mechanical Engineers [pdf!] where he notably talks about the rack-and-pinion mountain locomotives he developed in the 1990s whilst working for SLM. On the basis of "bums on seats" for a given weight of train up and down the Rothorn in Switzerland, the new steam locomotives are slightly more economical and pollute a lot less due to more complete combustion - all this with one-man operation for the locomotive. (They are also prettier and attract more customers, but this is not the main thrust of my argument.) They do use more fuel when working, but the gasoil burner is shut off when standing and when descending, retarding being done using the time-honoured Riggenbach counterpressure brake. With the burner off, heat and boiler pressure are conserved by radical heat insulation of boilers, cylinders and piping; comprehensive heat insulation is in fact crucial to all steam locomotives and was neglected in the past until Porta came along.

An on/off burner with electro-mechanical control was developed by the Doble brothers in the 1920s for their highly sophisticated steam cars. At 40 mph on the level they ran (I should say run, there are a still few on the go) burner-off for about two-thirds of the time. Modern electronics would make a multiple unit running with steam locomotives perfectly feasible. The ultra-modern Ezee (Equal Zero Emissions) steam unit using ceramic catalytic no-flame burners and ultra high pressure and temperature is designed to fit under the hood of a Skoda Fabia and was developed by IAV in the late 1990s by a research group subsidiary of Volkswagen. Try telling these people that the steam process is inefficient.

To go back to Waller, he has proposed a methane burning loco for Russia that promises a 60% economy over diesels or electrics - I don't think he was believed which is symptomatic of the communication problem we're facing.

Discomfort - working conditions

This was the biggest argument in the Fifties for doing away with steam and at that time was perfectly valid. There's no doubt that servicing Stephensonian steam locomotives (i.e. the "puffer" with firetube boiler) to keep the trains running was an absolute nightmare, especially in Britain and France where "facilities" had become worse than in the 19th Century. Porta and others have shown that today there is absolutely no excuse for such a state of affairs. Porta's most recent steam projects would have required very little servicing and gave very high mileage between overhauls.

One of the problems was the use of coal with its attendant dust, soot and ashes. Porta did not just develop the Gas producer system, he proposed automated devices for ash disposal and the whole boiler unit he developed eliminated almost all pollution (or "ambiental contamination" as he called it - he was an environmentalist before that word was invented) through complete combustion. His solutions were not armchair engineering but eminently practical, backed by sound theory and can be taken up again at any time (he wrote over 200 papers, so none of this is lost at the time of writing). Solid fuel burning does bring more problems than liquid fuel but IC engines cannot deal with solid fuel at all: although coal-dust burning diesels are theoretically possible and have been tried, they have never come to anything. Porta's steam locomotives on the hand have no trouble with solid, liquid or gas fuels of any kinds including biomass, and adapt to local conditions eliminating expensive pre-processing of the fuel. Most of the more recent projects burn gasoil, although as I write, Shaun McMahon at Rio Turbio, Patagonia is working hard on reviving the the gas producer system.

Outdated technology

This is what I take Migeru's obscure comment to imply (unfamiliar blog language misunderstood by me - sorry Migeru - anyway the point is still valid and reflects an attitude commonly encountered). Outdated to me smells of fashion and in assessing any technology, fashion has absolutely no place the debate. This does not mean that we should not be critical of the past but criticism can be positive as well as negative.

Over the last couple of years I have been translating an unpublished Porta manuscript paper in French centred around André Chapelon's celebrated 4-8-0 rebuilds (Andrée's a girl's name, Helen but there's no harm in wishful thinking, a few woman steam engineers would certainly be a breath of fresh air). I hope to find an interested publisher in the near future, but whether that happens or not, translating it has been an education in itself and the paper is interesting in being the only detailed criticism of Chapelon's work I have ever seen.

Chapelon himself was interested in history and always recognised his debt to the past. One name that comes up from time to time in his writings is D.K. Clark. Clark's most celebrated book is Railway Machinery published in 1855. He had been allowed to conduct tests on the locomotives of several railways around 1849 (lucky man) and the book is largely given over to his observations on the test results. Apart from the fact that high pressure for him was a mere 100 psi (7 bars), the book could almost have been written by Porta himself. Clark even developed a primitive form of Gas producer system. It wasn't his invention but he saw the value of it and applied it on the Great North of Scotland Railway around 1855 at a time when most railways were burning coke. Like Porta's GPCS, it used steam jets and air ducts and in a simplified form was used by the railway in question until it ceased to exist as an independent concern in 1923.

Another thing I totally reject when discussing steam is Helen's own closing comment that Porta's legacy is a "might-have-been". She mentioned David Wardale, the brain behind the brilliant 5AT project, but we also have Nigel Day, Phil Girdlestone, Ted Pritchard, Shaun McMahon, Roger Waller - all continuing Porta's work in various parts of the globe. Apart from Pritchard, these are not old men. They all love steam for its own sake, but much more than enthusiasts, they are also practising engineers, highly competent in a neglected, demanding and grossly misunderstood technology. The world has never been so much in need of this sort of competence.

Porta's motto was No hay que Flojar, which basically means, "Never throw in the sponge".