Pennsylvania class B6
United States 1902 372 produced
When it came to switchers, here called “shifters”, the PRR stuck to locomotives with a maximum of three axles, but still sufficient tractive power until the mid-20s. The most successful class here was the B6, of which a total of 372 were built between 1902 and 1920. It started with 79 of the basic B6, which were operated with saturated steam and had the Belpaire firebox typical of the PRR.
From 1913 onwards, 55 B6sa followed, which had a round firebox and were factory-built with a superheater. The largest number was reached by the B6sb with 238, which again had a Belpaire firebox. The B6 were also later rebuilt with superheaters and referred to as B6s. Today there are still two B6sa and B6sb, both of which are not operational.
Technical data
General
| Property | B6 | B6sa | B6sb |
|---|---|---|---|
| Built | 1902-1913 | 1913-1914 | 1916-1920 |
| Manufacturers | Altoona, Baldwin, Lima | Altoona | |
| Wheel arrangement | 0-6-0 (Six-coupled) | ||
| Gauge | 1,435 mm (Standard gauge) | ||
Dimensions and weights
| Property | B6 | B6sa | B6sb |
|---|---|---|---|
| Wheelbase | 3.51 m | ||
| Service mass | 77.1 t | 81.6 t | |
| Adhesion mass | 77.1 t | 81.6 t | |
| Rigid wheelbase | 3.51 m | ||
| Axle load | 25.7 t | 27.2 t | |
Boiler
| Property | B6 | B6sa | B6sb |
|---|---|---|---|
| Grate area | 3.828 m² | 5.76 m² | 5.723 m² |
| Evaporative heating surface | 228.449 m² | 174.937 m² | 177.166 m² |
| Total heating surface | 228.4 m² | 237.9 m² | 220.3 m² |
| Superheater surface | 62.988 m² | 43.107 m² |
Power plant
| Property | B6 | B6sa | B6sb |
|---|---|---|---|
| Driver diameter | 1,422 mm | ||
| Boiler pressure | 14.1 bar | ||
| Expansion type | simple expansion | ||
| Cylinders | two, 559 x 610 mm | ||
Power
| Property | B6 | B6sa | B6sb |
|---|---|---|---|
| Power source | steam | ||
| Estimated power | 671 kW (912 PS) | 1,044 kW (1,419 PS) | 969 kW (1,317 PS) |
| Starting effort | 160.8 kN | ||
Calculated values
| Property | B6 | B6sa | B6sb |
|---|---|---|---|
| Factor of adhesion | 1 : 4.71 | 1 : 4.98 | |
| Optimal speed | 26 km/h | 40 km/h | 37 km/h |
| Power-to-weight ratio | 8.7 kW/t | 12.8 kW/t | 11.9 kW/t |
| Adhesive weight/Total | 1 : 1.00 | ||
| Tractive force/Heating surface | 1 : 14.70 | 1 : 14.11 | 1 : 15.24 |
| Grate area/Heating surface | 1 : 59.68 | 1 : 41.31 | 1 : 38.49 |
| Total/Superheater | 1 : 2.78 | 1 : 4.11 | |
