Missouri-Kansas-Texas classes L-1a and L-1b
United States 1913 70 produced
In 1913 and 1914, the MKT received 60 Mikados from ALCO-Brooks with Walschaerts valve gear, which were listed as class L-1a. Their Number was augmented in 1914 by ten more, which received Baker valve gear and were listed as class L-1b because of this difference. They were initially coal fired but underwent a conversion to oil firing by 1922. The new tenders now held 2,990 gallons of oil instead of 14 short tons of coal and had a slightly smaller water reserve. The boiler pressure had meanwhile been increased from 185 to 195 psi.
Technical data
General
| Property | as built | rebuilt oil-fired |
|---|---|---|
| Built | 1913-1914 | 1922 |
| Manufacturers | ALCO | |
| Wheel arrangement | 2-8-2 (Mikado) | |
| Gauge | 1,435 mm (Standard gauge) | |
Dimensions and weights
| Property | as built | rebuilt oil-fired |
|---|---|---|
| Wheelbase | 10.69 m | |
| Total wheelbase | 21.53 m | |
| Service mass | 130.4 t | |
| Adhesion mass | 97.3 t | |
| Total mass | 207.3 t | 206.6 t |
| Rigid wheelbase | 5.03 m | |
| Axle load | 24.3 t | |
| Water capacity | 32,176 l | 30,283 l |
| Fuel capacity | 12.7 t (coal) | 11,318 l (oil) |
Boiler
| Property | as built | rebuilt oil-fired |
|---|---|---|
| Grate area | 5.342 m² | |
| Firebox surface | 23.226 m² | |
| Tube heating surface | 313.827 m² | |
| Evaporative heating surface | 337.053 m² | |
| Superheater surface | 82.405 m² | |
| Total heating surface | 419.5 m² | |
Power plant
| Property | as built | rebuilt oil-fired |
|---|---|---|
| Driver diameter | 1,549 mm | |
| Boiler pressure | 12.8 bar | 13.4 bar |
| Expansion type | simple expansion | |
| Cylinders | two, 673 x 762 mm | |
Power
| Property | as built | rebuilt oil-fired |
|---|---|---|
| Power source | steam | |
| Estimated power | 1,566 kW (2,129 PS) | 1,641 kW (2,231 PS) |
| Starting effort | 241.6 kN | 254.6 kN |
Calculated values
| Property | as built | rebuilt oil-fired |
|---|---|---|
| Factor of adhesion | 1 : 3.95 | 1 : 3.75 |
| Optimal speed | 40 km/h | |
| Power-to-weight ratio | 12.0 kW/t | 12.6 kW/t |
| Heating Surface Equivalent | 618.0 m² | |
| Cylinder volume/HSE | 1 : 877.51 | |
| Adhesive weight/Total | 1 : 1.34 | |
| Tractive force/Heating surface | 1 : 12.03 | 1 : 12.68 |
| Grate area/Heating surface | 1 : 78.52 | |
| Firebox/Tube surface | 1 : 13.51 | |
| Total/Superheater | 1 : 4.09 | |
