Data from M. A Mallet, " The Development of the Compound System in Locomotives," The Railroad and Engineering Journal, Vol LXV, No 5 (May 1891), pp. 202-204.
This little Mallet worked on the railway system set up to convey passengers around the grounds of the 1889 Paris Exposition. Like Eiffel's Tower, which was erected for the same fair, l' Avenir exerted an enduring influence. It was one of the very first to use the four-cylinder compounding system that would dominate articulated-locomotive operation for decades.
The locomotive was rated at 260 tons, pulling bogie passenger cars over a 3 km (1.9 mile) track on the grounds at a maximum 16 kph (10 mph) and 3.2 kph (2 mph) through the level (grade) crossings. Rails weighed 19 lb/yard (9.5 kg/metre) and were laid in 7.75 metre (25 ft 5 in) sections.
At least three of the articulated locomotives operating on the Chemins de fer du Calvados in Normandy had begun their careers on the Exposition Railway in 1889. Calvados numbers 1,m 2, and 6 (Cabourg, Salenelles, and Varaville, respectively) had been sold to the Tramways de Royan in 1891.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | l'Avenir |
| Locobase ID | 11383 |
| Railroad | Decauville RR at Paris Exposition |
| Country | France |
| Whyte | 0-4-4-0T |
| Number in Class | 8 |
| Road Numbers | |
| Gauge | 60 cm |
| Number Built | 8 |
| Builder | Decauville |
| Year | 1887 |
| Valve Gear | various |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 5.58 / 1.70 |
| Engine Wheelbase (ft / m) | 9.19 / 2.80 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.61 |
| Overall Wheelbase (engine & tender) (ft / m) | 9.19 / 2.80 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | |
| Weight on Drivers (lbs / kg) | 25,794 / 11,700 |
| Engine Weight (lbs / kg) | 25,794 / 11,700 |
| Tender Loaded Weight (lbs / kg) | |
| Total Engine and Tender Weight (lbs / kg) | 25,794 / 11,700 |
| Tender Water Capacity (gals / ML) | 370 / 1.40 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 11 / 5.50 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 23.60 / 600 |
| Boiler Pressure (psi / kPa) | 169.70 / 1170 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 7.48" x 10.24" / 190x260 |
| Low Pressure Cylinders (dia x stroke) (in / mm) | 11.02" x 10.24" / 280x260 |
| Tractive Effort (lbs / kg) | 4795 / 2174.98 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 5.38 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | |
| Firebox Area (sq ft / m2) | 24.76 / 2.30 |
| Grate Area (sq ft / m2) | 5.38 / 0.50 |
| Evaporative Heating Surface (sq ft / m2) | 240 / 22.30 |
| Superheating Surface (sq ft / m2) | |
| Combined Heating Surface (sq ft / m2) | 240 / 22.30 |
| Evaporative Heating Surface/Cylinder Volume | 460.82 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 913 |
| Same as above plus superheater percentage | 913 |
| Same as above but substitute firebox area for grate area | 4202 |
| Power L1 | 2148 |
| Power MT | 734.36 |