Data from in Wikipedia at [], last accessed 21 September 2024.
As small as they were, these little engines operated on the standard gauge pulling light passenger trains. Known as motoropotlo, which in Hungarian conveys the stocky image conveyed by a locomotive of such short length but standard width. They also were fitted with the first examples of the Brotan boiler, a boiler design described in more detail in Locobase 1580.
Wikipedia's account said that this class arose out of a need to haul suburban traffic over very lightly built. The MAV used small steam locomotives and internal-combustion railcars in the early 20th century. But, says Wikipedia, [in translation] "...in the event of motorcars breaking down or being out of service, their immediate replacement has already caused problems ...They wanted to help this situation by purchasing new locomotives, the main profile of which would have been primarily to replace the lost steam locomotives."
The motive power stud came in two batches--23 in 1910, 8 more in 1913. They proved quite successful in the short run, but after World War I ended, class size began to dwindle.
In the late 1920s, many of the class surrendered their compound systems in favor of two simple-expansion cylinders and a tiny superheater."The conversion significantly improved the locomotive's performance and consumption," reported Wikipedia.
"In the following years," wrote Wikipedia, "as steam locomotives were pushed into the background, their original assignment changed, so they appeared on more and more branch lines. They served primarily in the areas of Miskolc, Debrecen, Nyíregyháza, Mezotúr, but later they were transferred to the other side of the Danube, so they also appeared in the catchment area of ??Dombóvár, Siklós and Kaposvár."
By the end of World War II, only seven remained and they were soon scrapped.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | M1a/11/JDZ 160-001 |
| Locobase ID | 1537 |
| Railroad | Magyar Allamvasutak (MAV) |
| Country | Hungary |
| Whyte | 2-2-0T |
| Number in Class | 31 |
| Road Numbers | 11.001-11.031/JDZ |
| Gauge | Std |
| Number Built | 31 |
| Builder | MAVAG |
| Year | 1910 |
| Valve Gear | Heusinger |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | |
| Engine Wheelbase (ft / m) | |
| Ratio of driving wheelbase to overall engine wheelbase | |
| Overall Wheelbase (engine & tender) (ft / m) | |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | |
| Weight on Drivers (lbs / kg) | 21,275 / 9650 |
| Engine Weight (lbs / kg) | 42,770 / 19,400 |
| Tender Loaded Weight (lbs / kg) | |
| Total Engine and Tender Weight (lbs / kg) | |
| Tender Water Capacity (gals / ML) | 2 / 0.01 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 0.73 / 0.70 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 35 / 17.50 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 40.90 / 1039 |
| Boiler Pressure (psi / kPa) | 232.10 / 1600 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 8.66" x 15.75" / 220x400 (1) |
| Low Pressure Cylinders (dia x stroke) (in / mm) | 12.99" x 15.75" / 330x400 (1) |
| Tractive Effort (lbs / kg) | 3944 / 1788.97 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 5.39 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 80 - 1.811" / 46 |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | 6.56 / 2 |
| Firebox Area (sq ft / m2) | 54.14 / 5.03 |
| Grate Area (sq ft / m2) | 8.40 / 0.78 |
| Evaporative Heating Surface (sq ft / m2) | 277 / 25.73 |
| Superheating Surface (sq ft / m2) | 56 / 5.20 |
| Combined Heating Surface (sq ft / m2) | 333 / 30.93 |
| Evaporative Heating Surface/Cylinder Volume | 515.96 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 1950 |
| Same as above plus superheater percentage | 2281 |
| Same as above but substitute firebox area for grate area | 14,702 |
| Power L1 | 13,775 |
| Power MT | 1427.43 |