Bugatti Automotrice Review and Discussion

In some circles of Parisian society it was fashionable to say, “I’m taking the Bugatti to Deauville”…

By Pete Vack

Read Part 1

We hope that Part 1 of our review has whetted your interest in Bugatti railcars. This week we’ll answer a few of the questions concerning their design and operation. Think banana tappets* as we reveal a few innovations…to see them all, do buy the book as it’s worth every cent…

For this reviewer, one of the most vexing of the Bugatti patents were the two-piece wheels insulated from each other by rubber, implying that there was no metal to metal contact between an inner and out wheel. Ok, it sounds great, taken from the Michelin idea to have railcars ride on actual rubber wheels, but without seeing the patent drawings or cutaways, it was difficult to imagine how steel or cast iron railway wheels separated with rubber inserts, being subjected to the heat of brakes, weight, centrifugal force, water and oil, could last more than a few laps. Visions of oily, sagging, broken automobile motor mounts entered the mind’s eye. Eric Favre answers this question, providing a detailed diagram and discussing the problems encountered with the rubber bumper buggy wheels.

The braking system devised by Bugatti. The brakes were applied by use of the handle at left, augmented by an air pressure brake cylinder.

Which brings us to the brakes. After inventing his own albeit unsuccessful hydraulic brake system, Bugatti returned to his beloved cable operated brakes. In general, while effective enough when adjusted properly and all systems were go, cable brakes got out of whack quite easily and lost the initial braking power. Yet Ettore Bugatti figured they were good enough for his automotrice. And can you imagine the cables, stretching from the eight wheel bogie to the control panel? How good were they? Good enough not to be replaced by hydraulic brakes or even the Westinghouse air brake common to most trains.

The bogies were special as well. There were four axles and eight wheels, each with two sets of four wheels suspended by leaf springs. We are not sure if the wheels would be considered unsprung weight but I doubt it. Adapting automobile suspension technology to a railcar was unusual, and the Bugatti railcars were reportedly the best handling ever. Chalk one up for Ettore.

Two different drivetrain layouts were used for the big WR 800 hp-each engine produced 200 hp.

Engine layout. While most, if not all, railcars made use of only one diesel powerplant, Bugatti’s idea to use four Royales powered with an expensive concoction of gas and alcohol, the drive train bears investigation. Bugatti had several different layouts, the most efficient, one might guess, was the inline with the driveshaft to the bogie, eliminating the immediate 90 degree angle of the transverse layout first used on the WR Presidential. And this in turn led us to consider the means of controlling the torque curve, i.e., what was used for the transmission and clutch. Despite the fact that the 200 hp 12.7 liter Royale engine produced a prodigious amount of torque, was it enough to move a railcar with a transmission? The partial answer was to use a Daimler Benz automatic hydraulic converter, which also must have sopped up a lot of power, hence four engines. Later, a Cotal gearbox was used as well particularly on the less powerful twin engine WLG 400s.

The control room. The operator apparently stood on the landing, and looked out from the cupola seen near the top of the drawing. The handbrake is number 8.

Now, with two or four engines to control at one time, it must have kept the operator or engineer quite busy. From his cupola in the center of the automotrice, he had a lot to do. That it is difficult to connect and simultaneously control two engines in a race or road car is well known; but very little is imparted as to how four Royale engines faired when it came to synchronized acceleration and shifting. Thinking along these lines, one might assume that a railcar engine with a torque converter may have a lot more leeway with throttle response than, say, a racing car. But railcar experts we are not.

Three Royale-Automotrice engines on the assembly line. It is very doubtful that Bugatti would have constructed 23 or so engines for the ill fated Royale, of which only 6 were made before the crash of ’29.

So for each of the WRs, Ettore Bugatti got rid of four of the 23 previously useless Bugatti La Royale engines which seemed to be just sitting around after the crash of 1929 and the dismal failure of the La Royale itself. But oops, wait a minute. For years, it was thought by many that Bugatti went into the automotrice business simply because he had to do something with the extra Royale engines, built or being built, or so said Rene Dreyfus in the aforementioned SCI article, which in turn was then quoted by Griff Borgeson in his controversial Bugatti book. But Eric Favre found sufficient evidence to the contrary, in addition to common sense, i.e., would Bugatti actually have built up 20 plus engines for chassis with no orders? Of course not, says Favre, and Bugatti designer Noel Domboy confirmed that it was not the engines, but the tooling for the engines that could be utilized for a railcar and therefore the cost amortized. Furthermore, Bugatti had been interested in railcars for years, and jumped at the chance to get into a contest with Michelin and Renault, knowing that he could build a better automotrice than anyone else.

And you wanted to know how many are left and where they are? It would be nice if a Bugatti collector might have purchased a few examples for his collection, say at least one WR 800 and another WLG 400. But collecting trains is an altogether different adventure. Suffice to say, the Bugatti automotrices suffered a slow decline after WWII and by 1958 the last WG was taken out of service. As far as anyone knows, all but one were scrapped. XB1008 remains, and can be seen at the Musée des Chemins de Fer (Railway Museum), now the Cité du Train at Mulhouse, close to the Musée National de l’Automobile.

We have but scratched surface of Favre’s remarkable and most welcome book. There are plenty of details about costs, contracts, specifications, and wonderful photos of the interiors of the various automotrices. No wheel, rubber insulated or not, is left unturned. The Bugatti railcar was a very significant factor in the life of Ettore (and Jean) Bugatti, the factory at Molsheim, and a boon to the financial status, saving, for at least a while, Bugatti race and road cars until the war. This book belongs in any Bugatti oriented library.

Yes, we recommend the book! Here’s how to order:

Automotrices Bugatti, “Les Pursang” du Rail” by Eric Favre
Self published, 336 pages, over 400 illustrations, slipcase
U.S. customers, order direct from Donald Toms, don@bugattibooks.com, 941-727-8667, Florida $165 Post Paid
All others: Price: €99,90 plus shipping costs €8,00 for France (Mondial Relay) and Europe, and €12,00 for the rest of the world.
For further information and to order: favreric@aol.com

*