I doubt this one survived, but certainly an unusual looking locomotive, here in 1939:

http://abpr.railfan.net/abprphoto.cgi?j ... anColl.jpg

Still a nice looking engine. The valve gear appears to a bit unusual as well.

That is correct, none of them have survived. Gavin can tell us more about it; but members of this class were some of the most advanced Garratts ever built. Notice the boiler feedpump for the french-built ACFI feedwater heater on the smokebox side; I think it had a coal pusher and other wonderful gadgets.

Bob has done me proud today! The valve gear is Cossart, which had vertical piston valves and was electrically controlled (a recipe for disaster if there ever was one). I always understood that they had rotary bunkers (notice the doors which are open in the picture). I also read that they had two firedoors and carried two firemen. I'd love to see a picture of the cab layout. I've got no disposal dates/details for them but it seems that they fell by the wayside in the mid to late 1940's - though I'm open to correction........

Durrant described them as "gadget infested"....

There is a link (in French) on these engines:
http://alger-roi.fr/Alger/transports/ch ... gamt73.htm
with the main specs + a list of info sources.
A few basic infos translated:
There was 2 types of Garrats in ALG:
- 482-284 gauge 1.05 for the Blida-Djelfa line, built 1932, lasted till about 1960. Number of engines not mentioned on the link.
- 462-264 standard Gauge, not clear whether the prototype was ment for the PLM in mainland France or tried there, but she did run in France and there are quite a few pics of these trials. Once proven right fror the ALG mainlines (run by a subsidiary of the French PLM), 29 more engines were delivered between 1936 and 1940. Lasted till 50's, the link just says there was many problems with the water available in ALG and the engines were difficult to maintain so disappeared fast once diesels set in.
To the best of my knowledge none has survived even as hulk
JF Andrist

Here are some specs I found:

Class 231-132BT

Tractive effort: 65,960 lb
Axle load: 40,500 lb
Drivers: 71" dia
Heating surface: 2,794 sq. ft.
Superheater: 975 sq ft.
Operating pressure: 284 psi
Grate area: 58 sq ft.
Fuel: 24,000 lb
Water 6,600
Adhesive weight: 241,000 lbs
Length: 96'-67/8"

The electricly operated Cossart valve gear could achieve cut-off in the 5-7 percent range (Conventional runs 15-17 percent)

The cab featured duplicate controls

feedwater heater

A turbo fan for ventilating the cab

Drench pipes in the Ash pan and smoke box

A soot blower to clean the tubes

Double blast pipe and stack (side by side rather than one behind the other)

coal pusher

While testing on the Northern Railway bnetween Calais and Paris it developed a steady 3000 hp

A very impressive design indeed!

Thirty were built all were out of sevice by the early 50's

Oh to have one know!

1.05m 241-142YAT class - 4 were built. Recently a French modeller has scratch built this in HOm scale: http://users.powernet.co.uk/hamilton/bgpix/mv.jpg

There is also this incomplete live steam model of a 231-132BT class displayed at the l'Écomusée du Creusot, Borgogne, France: http://users.powernet.co.uk/hamilton/bg ... arratt.jpg

Thanks for the additional information in the link - I can generally follow written French but not very quickly.

I wish I could have seen one "in the flesh"

Thanks for the extra details.

I have compiled a table of dimensions of all Garratt's built (where I could find them) which was not a fun task! Link here: http://users.powernet.co.uk/hamilton/dimensions.html

Can anyone explain the "electrically controlled" valve gear?

Steven,

I'm pretty sure the engines used an electric servo motor to change the valve cutoff. This was basically an electric version of a power reverse.

Cossart valve gear uses small, vertically mounted piston valves at each end of the cylinder with separate valves for admission and exhaust. The separate valves for admission and exhaust is what allowed the very short cutoffs mentioned in the post above. The valves are actuated by a rotary camshaft which is mounted in the cylinder block parallel to the engine's axles. The cam is driven by the long weird-looking rod with lightening holes in it on either side of the engine. This rod is driven from an eccentric on the main driver. The cool thing about these is that in addition to driving the camshaft for the valve gear, they also partially compensate for the imbalance of the engine's reciprocating parts as these rods are always moving in the opposite direction of the main rods.

These were NEAT engines but it's easy to see why they ran into operational problems given their level of sophistication and the environment they had to operate in.