Buffalo, Rochester & Pittsburgh class XX
Baltimore & Ohio class EE-2a
The 2-8-8-2 Mallets built by ALCO-Brooks in 1918 for the BR&P were among the heaviest locomotives in the world when they were built. They had drivers of 57 inches and cylinder diameters of 28 and 44 inches, with a stroke of 32 inches. The firebox had a grate of 99.2 square feet and a direct heating surface of 410 square feet. Additionally there were arch tubes with a total surface of 69 square feet. A Duplex stoker was installed to feed such a huge boiler. The valve gear was operated by a Ragonnet & Mellin power reverser.
They were rated to haul 140 empties or 70 loaded cars over a 1.1% incline of 17 miles. Although the railroad originally planned to order 15 of these locomotives, the first order only included seven locomotives which were delivered in March and April 1918. Two more were delivered in September 1923 which were somewhat heavier, but otherwise identical. Running numbers were 800 to 808. When the BR&P was bought by the Baltimore & Ohio in 1932, they became class EE-2a No 7316 to 7324. They were scrapped in 1950 and 1951.
Technical data
General
| Property | 800-806 | 807-808 |
|---|---|---|
| Built | 1918 | 1923 |
| Manufacturers | ALCO | |
| Wheel arrangement | 2-8-8-2 (Mikado Mallet) | |
| Gauge | 1,435 mm (Standard gauge) | |
Dimensions and weights
| Property | 800-806 | 807-808 |
|---|---|---|
| Length | 31.18 m | |
| Wheelbase | 17.50 m | |
| Total wheelbase | 27.86 m | |
| Service mass | 258.1 t | 260.8 t |
| Adhesion mass | 226.8 t | 227.9 t |
| Total mass | 351.4 t | 354.1 t |
| Rigid wheelbase | 4.72 m | |
| Water capacity | 45,425 l | |
| Fuel capacity | 12.7 t (coal) | |
Boiler
| Property | 800-806 | 807-808 |
|---|---|---|
| Grate area | 9.216 m² | |
| Firebox surface | 44.501 m² | |
| Tube heating surface | 572.562 m² | |
| Evaporative heating surface | 617.063 m² | |
| Superheater surface | 151.618 m² | |
| Total heating surface | 768.7 m² | |
Power plant
| Property | 800-806 | 807-808 |
|---|---|---|
| Driver diameter | 1,448 mm | |
| Boiler pressure | 13.8 bar | |
| Expansion type | compound | |
| Cylinders | four, HP: 711 x 813 mm and LP: 1,118 x 813 mm | |
Power
| Property | 800-806 | 807-808 |
|---|---|---|
| Power source | steam | |
| Estimated power | 2,535 kW (3,447 PS) | |
| Starting effort | 473.8 kN | |
| Starting effort simple | 568.5 kN | |
Calculated values
| Property | 800-806 | 807-808 |
|---|---|---|
| Factor of adhesion | 1 : 3.91 | 1 : 3.93 |
| Optimal speed | 32 km/h | |
| Power-to-weight ratio | 9.8 kW/t | 9.7 kW/t |
| Heating Surface Equivalent | 1,142.8 m² | |
| Cylinder volume/HSE | 1 : 1,262.80 | |
| Adhesive weight/Total | 1 : 1.14 | |
| Tractive force/Heating surface | 1 : 15.45 | |
| Grate area/Heating surface | 1 : 83.41 | |
| Firebox/Tube surface | 1 : 12.87 | |
| Total/Superheater | 1 : 4.07 | |