Atlantic Coast Line class P-5-B
The Atlantic Coast Line was one of the few US railroads which used Pacific locomotives for dual service. The P-5-B was the successor of the P-5-A that had been of the USRA Light Pacific design. The P-5-B had a driver diameter of only 69 instead of 73 inches to be used in freight service. In the case of the ACL these were often light and fast trains with agricultural products.
The weight on the drivers could be changed by pins which in turn increased or decreased the weight on the leading truck and trailing axle. This changed the maximum axle load by nearly 4,000 pounds. The newer batches also had a booster. Of 165 locomotives built, the first 70 had Baker valve gear and the rest had Walschaerts. They were retired between 1950 and 1953.
Technical data
General
| Property | low axle load | high axle load | with booster |
|---|---|---|---|
| Built | 1922-1926 | ||
| Manufacturers | Baldwin | ||
| Wheel arrangement | 4-6-2 (Pacific) | ||
| Gauge | 1,435 mm (Standard gauge) | ||
Dimensions and weights
| Property | low axle load | high axle load | with booster |
|---|---|---|---|
| Length | 24.63 m | ||
| Wheelbase | 10.64 m | ||
| Total wheelbase | 21.59 m | ||
| Empty mass | 113.8 t | 121.3 t | |
| Service mass | 127.3 t | 131.9 t | |
| Adhesion mass | 80.5 t | 85.8 t | 90.9 t |
| Total mass | 212.6 t | 217 t | |
| Rigid wheelbase | 3.96 m | ||
| Axle load | 27 t | 28.7 t | 30.5 t |
| Water capacity | 37,854 l | ||
| Fuel capacity | 14.5 t (coal) | ||
Boiler
| Property | low axle load | high axle load | with booster |
|---|---|---|---|
| Grate area | 6.197 m² | ||
| Firebox surface | 25.037 m² | ||
| Tube heating surface | 271.463 m² | ||
| Evaporative heating surface | 295.943 m² | 296.5 m² | |
| Superheater surface | 73.765 m² | ||
| Total heating surface | 369.7 m² | 370.3 m² | |
Power plant
| Property | low axle load | high axle load | with booster |
|---|---|---|---|
| Driver diameter | 1,753 mm | ||
| Boiler pressure | 14.5 bar | ||
| Expansion type | simple expansion | ||
| Cylinders | two, 635 x 711 mm | ||
Power
| Property | low axle load | high axle load | with booster |
|---|---|---|---|
| Power source | steam | ||
| Estimated power | 2,163 kW (2,941 PS) | ||
| Starting effort | 201.4 kN | ||
| Starting effort booster | 54.268 kN | ||
Calculated values
| Property | low axle load | high axle load | with booster |
|---|---|---|---|
| Factor of adhesion | 1 : 3.92 | 1 : 4.18 | 1 : 4.43 |
| Optimal speed | 66 km/h | ||
| Power-to-weight ratio | 17.0 kW/t | 16.4 kW/t | |
| Heating Surface Equivalent | 569.2 m² | ||
| Cylinder volume/HSE | 1 : 791.38 | ||
| Adhesive weight/Total | 1 : 1.58 | 1 : 1.48 | 1 : 1.45 |
| Tractive force/Heating surface | 1 : 11.38 | 1 : 11.36 | |
| Grate area/Heating surface | 1 : 59.66 | 1 : 59.75 | |
| Firebox/Tube surface | 1 : 10.84 | ||
| Total/Superheater | 1 : 4.01 | 1 : 4.02 | |
