Fire Drake Files No.5 - CFD Vivarais Mallet

Mallet 403 awaits to take us out of the Ardeche hills at Lamastre

Articulated steam railway engines have appealed to me from an early age when I discovered A E Durrant's book on Beyer-Garrett locomotives on the mobile library that used to come to our village. Wouldn't the steam come out when they articulate?

And Beyer-Garratts were not the biggest - that accolade belonged to the semi-articulated Mallets.

Mallets are pronounced malaise actually but Anglo-Cornish/Cornu-Saxon force of habit still makes me describe then as Mallets - as in the hammer - even though I now know better. I have in mind the hammer blows their great cranks must make on the track as the wheels go round but, in reality, one of the virtues of a Mallet was that it suited lightly laid tracks.

CFD Vivarais 403 is a classic mallet design with large, low pressure cylinders in front and smaller, high pressure cylinders behind. For a French engine it looks remarkably neat but then it was built in Switzerland.

Durrant also wrote a book about the Mallet locomotive and I now have my own copy, recently bought on good old Ebay while nobody else was looking. This book is highly sought after so often expensive.

I like the way Durrant writes. Here is a man who knows his subject and ferrets out there are facts if facts are to be dragged squealing into his burrow. He likes to know the whys and wherefores behind design evolution and expresses frustration at previous writers who state just the factual chronology.

Mallets could be enormous like the famous Big Boys of the Union Pacific Rail Road. Or they could be less overwhelming and run on the narrow gauge.

A few years ago, whilst visiting friends in France, I hit upon the idea of popping down to the Vivarias to see a gen-yew-ine Mallet. Nobody else was interested so I set out alone and found that their appreciation of distance sur le continent was better than mine. I had to camp overnight in my van to get there but I still reckon it was worth it.

While everyone's gone for a slap up meal in Lamastre, the preserved engine slumbers with damped down fire. In the background, the disused line to Le Cheylard stretches into the distance.

The metre-gauge Chemin du Fer Vivarais lies in the mountainous region of the Ardeche. I had to cross these hills to get to the principal terminus at Tournon, south of Lyons on the River Rhône. Finding the station was easy and for a small supplement I chose to ride in a first class carriage, which I shared with a most agreeable French family.

The line shares the standard gauge SNCF metals across a bridge over the River Doux and then curves away into the hills along the river valley. After a two hour journey we pulled into Lamastre, a gastronomic town with a reputation beyond its size 33kms (21 miles) into the wild country from Tournon. There was also a stop at Colombier le Vieux where local traders brought all manner of high class foody things for the passengers to buy. They didn't seem all that expensive.

Those large low pressure cylinders again. The visual potency of a Mallet engine is associated with the size of these. 403 is a well balanced design. Others are pure brutes.

But it was the Mallet, I'd come to see, old 403, built for the line back in 19xx, not in France but SLM Winterthur the Swiss manufacturer (works no. 1492). 403 is an 0-6-6-0T and is an example of the classic Mallet type with high pressure cylinders driving the rear wheels and bigger, low pressure cylinders driving the front. It was built in March 1903 and worked on the line all its life going straight into preservation in 1969. It weighs 44 tonnes in working order and on test could haul a 160 tonne train up a 1 in 34 gradient. Two others of the same class belong to the CFD Vivarais and, although one has been cannibalised for parts, the plan is to get all three into working order..

To be honest, I can't usually tell if a steam, diesel or electric engine is pulling the train I'm on but on the CFD Vivarais I felt that it could only really be a Mallet locomotive. There was the sound and the smuts and if you stood on the open platforms at the ends of the carriages you could see the engine working at the head of the train as the track snaked its way along the gorge, searching valiantly for the path of least resistance.

A E Durrant makes the point that Anatole Mallet didn't set out to build an articulated locomotive. His real interest lay in compounding steam i.e. using it twice. He started by building small two cylinder engines of conventional appearance that had a small, high pressure cylinder on one side and a large, low pressure one on the opposite side but, although similar engines were built for some 60 years, Monsieur Mallet thought he could go a stage further. His solution was an elegant acceptance of technological limitations of the time. Instead of two compound cylinders, he fitted four and gave them a wheel set each, the front set being pivoted at its training end with flexibly-jointed steam pipes. As these carried the low pressure exhaust steam from the high pressure cylinders, the joints were less likely to leak.

Below the smokebox is the articulated steam pipe for the front cylinders

Subsequent developments in the USA used no compounding, which annoyed Mallet no end. But by then he was an old man who could look back with satisfaction at conceiving the mostly numerous articulated type of steam locomotive.

I was dismayed to discover recently that the CFD Vivarais is currently closed. It seems the Mallet engines need expensive repairs and while funding is sought staff have been laid off and saplings are beginning to grow on the track. There's also some fuss about the three rail track (or tronc commun) shared with SNCF.

It all seemed so confident when I journeyed on it back in 2002.

Walschaerts valve gear features on both wheel sets but the low pressure cylinders have slide valves while the high pressure ones have piston valves and a more rounded outline

When it re-opens, I recommend you book ahead for a meal in Lamastre. I didn't and wandered around the town for a couple of hours wondering where everyone was. Gradually the place came back to life and the splendid green engine set off for Tournon. My fellow travellers were feeling very mellow by now and attempted conversation in English to which I responded in dreadful French. We discussed garden gnomes and the Loch Ness Monster (the French love Nessie) and whenever a belvedere hove into view I got pride of place because I was waving a camera about.

I think the problems facing the CFD Vivarais will be overcome. It seems to be in the interests of everyone that they should be. There is a campaign to raise the necessary and resume running. In the meantime, I'm really glad I went when I did and saw a narrow gauge Mallet working in its natural environment in the country of its birth.

My interest in articulated steam remains stronger than ever.