Seaboard Air Line class A
Baltimore & Ohio class EL-6a
In 1918, the Seaboard Air Line received 16 2-8-8-2 Mallets from ALCO-Richmond to move fast, heavy freights on their main line between Richmond, Virginia and Hamlet, North Carolina. After the wartime traffic had ended, it became clear that the SAL didn't have many uses for them since they were too heavy for many of their secondary lines and didn't fit the clearances in many places.
So all were sold to the B&O in 1920 and only two years later, they were rebuilt to class EL-6a. In this process, they got the wheel arrangement 2-8-8-0 by removing the trailing axle. This considerably increased the adhesive weight and at the same time they were simpled and got a higher boiler pressure, what also increased their starting tractive effort. In this form, they were used until 1954.
Technical data
General
| Property | as built | B&O EL-6a |
|---|---|---|
| Built | 1918 | 1922 |
| Manufacturers | ALCO | Martinsburg |
| Wheel arrangement | 2-8-8-2 (Mikado Mallet) | 2-8-8-0 (Bull Moose) |
| Gauge | 1,435 mm (Standard gauge) | |
Dimensions and weights
| Property | as built | B&O EL-6a |
|---|---|---|
| Wheelbase | 16.26 m | |
| Total wheelbase | 29.95 m | |
| Service mass | 225.4 t | 223.2 t |
| Adhesion mass | 172.4 t | 207.2 t |
| Total mass | 324.8 t | 322.5 t |
| Rigid wheelbase | 4.71 m | |
| Axle load | 21.5 t | 27.8 t |
| Water capacity | 45,425 l | |
| Fuel capacity | 18.1 t (coal) | |
Boiler
| Property | as built | B&O EL-6a |
|---|---|---|
| Grate area | 8.175 m² | |
| Firebox surface | 36.325 m² | 36.975 m² |
| Tube heating surface | 516.448 m² | 513.197 m² |
| Evaporative heating surface | 552.774 m² | 550.172 m² |
| Superheater surface | 135.639 m² | 128.206 m² |
| Total heating surface | 688.4 m² | 678.4 m² |
Power plant
| Property | as built | B&O EL-6a |
|---|---|---|
| Driver diameter | 1,600 mm | |
| Boiler pressure | 14.5 bar | 15.5 bar |
| Expansion type | compound | simple expansion |
| Cylinders | four, HP: 673 x 813 mm and LP: 1,067 x 813 mm | four, 635 x 813 mm |
Power
| Property | as built | B&O EL-6a |
|---|---|---|
| Power source | steam | |
| Estimated power | 2,237 kW (3,041 PS) | 2,312 kW (3,143 PS) |
| Starting effort | 405.2 kN | 540.1 kN |
| Starting effort simple | 486.2 kN | |
Calculated values
| Property | as built | B&O EL-6a |
|---|---|---|
| Factor of adhesion | 1 : 4.17 | 1 : 3.76 |
| Optimal speed | 34 km/h | 26 km/h |
| Power-to-weight ratio | 9.9 kW/t | 10.4 kW/t |
| Heating Surface Equivalent | 1,005.7 m² | 991.5 m² |
| Cylinder volume/HSE | 1 : 1,297.59 | 1 : 1,038.50 |
| Adhesive weight/Total | 1 : 1.31 | 1 : 1.08 |
| Tractive force/Heating surface | 1 : 12.29 | 1 : 16.63 |
| Grate area/Heating surface | 1 : 84.21 | 1 : 82.98 |
| Firebox/Tube surface | 1 : 14.22 | 1 : 13.88 |
| Total/Superheater | 1 : 4.08 | 1 : 4.29 |
