Data from the Sofia Locomotive Depot -- [] -- that takes as its mission the preservation of steam locomotive heritage from rust and theft. As with many Continental locomotives, the Anglo-Saxon should add 8-10% to the evaporative heating surface to allow proper comparison of this "fire-side" area with the "water-side" area used in Great Britain, its colonies, and North America.
This class of hefty freight haulers were the largest and most powerful locomotives to travel on such a narrow gauge. They were similar to, and in some way "descended" from, the German "Saxon" locomotives of the same arrangement that began construction in 1928 and traveled on the 75 cm gauge; see Locobase 4926.
The first five were ordered from Schwartzkopff on 27 October 1939 with delivery coming in the beginning of 1941. The Sofia Locomotive Depot account comments that although there was a delay in their delivery, their impact was immediate on the Saraniovo-Belitza and Varvar-Pazardjik lines, with a ton-mile increase over the next 3 years from 25 million to 43 million.
Plans to increase the stud of these powerful engines of course ran afoul of the chaos that enveloped Eastern Europe as the Second World War turned against the Third Reich. Only after peace and Soviet occupation of most of Eastern Europe had the situation stabilized sufficiently to order ten more from Peirwsza Fabryka Lokomotyw W Polsce's Chrzanow factory in late 1949. At that there were still problems with theft, including the leather seat covers and all the rubber tubing from the first two engines, after which the remaining eight were escorted as they were transported by rail car.
The Sofia site gives the details of this class's success in service. Suffice to say it was both considerable and enduring, with the first eight only being withdrawn in 1977. Two were saved for museums and one of these was extensively overhauled and reentered tourist service in the early 2000s.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | 600.76 |
| Locobase ID | 10342 |
| Railroad | BDZ |
| Country | Bulgaria |
| Whyte | 2-10-2T |
| Number in Class | 15 |
| Road Numbers | 601.76 - 615.76 |
| Gauge | 76 cm |
| Number Built | 15 |
| Builder | several |
| Year | 1941 |
| Valve Gear | Heusinger |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 13.78 / 4.20 |
| Engine Wheelbase (ft / m) | 26.25 / 8 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.52 |
| Overall Wheelbase (engine & tender) (ft / m) | 26.25 / 8 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | 22,046 / 10,000 |
| Weight on Drivers (lbs / kg) | 110,231 / 50,000 |
| Engine Weight (lbs / kg) | 136,686 / 62,000 |
| Tender Loaded Weight (lbs / kg) | |
| Total Engine and Tender Weight (lbs / kg) | |
| Tender Water Capacity (gals / ML) | 1848 / 7 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 4.40 / 4 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 37 / 18.50 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 33.50 / 850 |
| Boiler Pressure (psi / kPa) | 227.70 / 1570 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 18.11" x 15.75" / 460x400 |
| Tractive Effort (lbs / kg) | 29,844 / 13537.03 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 3.69 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | |
| Firebox Area (sq ft / m2) | |
| Grate Area (sq ft / m2) | 21.52 / 2 |
| Evaporative Heating Surface (sq ft / m2) | 943 / 87.60 |
| Superheating Surface (sq ft / m2) | 351 / 32.60 |
| Combined Heating Surface (sq ft / m2) | 1294 / 120.20 |
| Evaporative Heating Surface/Cylinder Volume | 200.83 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 4900 |
| Same as above plus superheater percentage | 6223 |
| Same as above but substitute firebox area for grate area | |
| Power L1 | |
| Power MT | |