Atlanta, Birmingham & Atlantic No. 1601 to 1624
Atlantic Coast Line classes AW-3 and AW-4
The largest class of steam locomotives ordered by the Atlantic & Birmingham Railroad were 24 ten-wheelers which were numbered 1601 to 1624. They were built by Baldwin in 1906 and 1907, had drivers with a diameter of 63 inches and cylinders which measured 21 inches in stroke and 28 inches in diameter. When this railroad became the Atlanta Birmingham & Atlantic in 1914, they were renumbered to 66 to 89. There they were superheated and their Stephenson valve gear was replaced by the Baker-Pilliod design. The cylinder diameter was increased to 23 inches and ten of the locomotives received larger drivers with a diameter of 67 inches.
In 1926, the AB&A was acquired by the Atlantic Coast Line and renamed to Atlanta Birmingham & Coast. There the locomotives became numbers 101 to 124. When the railroad was fully incorporated into the ACL, the six remaining locomotives with 63-inch drivers became class AW-3, the nine with 67-inch drivers became AW-4. They were retired between 1946 and 1952.
Technical data
General
| Property | as built | superheated |
|---|---|---|
| Built | 1906-1907 | |
| Manufacturers | Baldwin | |
| Wheel arrangement | 4-6-0 (Ten-wheeler) | |
| Gauge | 1,435 mm (Standard gauge) | |
Dimensions and weights
| Property | as built | superheated |
|---|---|---|
| Wheelbase | 7.82 m | |
| Total wheelbase | 16.99 m | |
| Service mass | 81.6 t | 84.5 t |
| Adhesion mass | 60.8 t | 66.6 t |
| Total mass | 136.1 t | 136.6 t |
| Rigid wheelbase | 4.47 m | |
| Water capacity | 18,927 l | 22,712 l |
| Fuel capacity | 10 t (coal) | |
Boiler
| Property | as built | superheated |
|---|---|---|
| Grate area | 2.936 m² | |
| Firebox surface | 18.116 m² | |
| Tube heating surface | 251.024 m² | 188.686 m² |
| Evaporative heating surface | 269.14 m² | 206.802 m² |
| Total heating surface | 269.1 m² | 246.7 m² |
| Superheater surface | 39.855 m² | |
Power plant
| Property | as built | superheated |
|---|---|---|
| Driver diameter | 1,600 mm | |
| Boiler pressure | 15.2 bar | 12.8 bar |
| Expansion type | simple expansion | |
| Cylinders | two, 533 x 711 mm | two, 584 x 711 mm |
Power
| Property | as built | superheated |
|---|---|---|
| Power source | steam | |
| Estimated power | 820 kW (1,115 PS) | 895 kW (1,217 PS) |
| Starting effort | 163.0 kN | 164.5 kN |
Calculated values
| Property | as built | superheated |
|---|---|---|
| Factor of adhesion | 1 : 3.66 | 1 : 3.97 |
| Optimal speed | 31 km/h | 34 km/h |
| Power-to-weight ratio | 10.0 kW/t | 10.6 kW/t |
| Heating Surface Equivalent | 359.7 m² | 377.1 m² |
| Cylinder volume/HSE | 1 : 883.59 | 1 : 1,011.08 |
| Adhesive weight/Total | 1 : 1.34 | 1 : 1.27 |
| Tractive force/Heating surface | 1 : 12.65 | 1 : 13.93 |
| Grate area/Heating surface | 1 : 91.67 | 1 : 84.01 |
| Firebox/Tube surface | 1 : 13.86 | 1 : 10.42 |
| Total/Superheater | 1 : 5.19 |