Kenya-Uganda Railway classes EC, EC1 and EC2
East African classes 50, 51 and 52
The unsatisfactory results of the unreliable and high-maintenance M-class Mallets led the Kenya-Uganda Railway to switch to Garratt-type locomotives. They weighed over 120 tons loaded, had a Belpaire firebox and were among the most powerful meter gauge locomotives of their time. The first four to be delivered came in 1926 from Beyer, Peacock & Co. and were designated class EC. They were fired with eucalyptus wood, which soon proved inefficient and dangerous for the crew. Thus, a conversion to coal firing took place, but they were already sold to Indochina in 1939.
20 of the class EC1 were purchased in 1927, which were essentially identical to the EC but were coal-fired from the start. Two more followed in 1930, which differed from the 1927 batch in minimal details. For this reason, the East African Railways made the first batch the class 50 and the second batch became class 51. Ten more oil-fired locomotives followed in 1931, which ran as EC2 on the KUR and later became class 52 on the EAR.
With the Garratts, the train loads could be significantly increased compared to the older locomotives. Up to 440 tons could now be hauled on the non-upgraded stretches with a gradient of up to two percent, on which the older eight-coupled vehicles could haul a maximum of 200 tons. They also hauled passenger trains at higher speeds on the upgraded line between Mombasa and Nairobi. They were mostly phased out in the 1950s and some of the bogies were reused to rebuild class 13 tank locomotives from a 4-8-2 to 4-8-4 wheel arrangement.
Technical data
General
| Property | EC | EC1 | EC2 |
|---|---|---|---|
| Built | 1926 | 1927, 1930 | 1931 |
| Manufacturers | Beyer, Peacock & Co. | North British | |
| Wheel arrangement | 4-8-2+2-8-4T (Double Mountain (Garratt)) | ||
| Gauge | 1,000 mm (Meter gauge) | ||
Dimensions and weights
| Property | EC | EC1 | EC2 |
|---|---|---|---|
| Wheelbase | 15.14 m | ||
| Service mass | 127.4 t | 133 t | 144.4 t |
| Adhesion mass | 80.7 t | 85.2 t | 89.4 t |
| Rigid wheelbase | 3.73 m | ||
| Water capacity | 19,321 l | 22,845 l | 23,867 l |
| Fuel capacity | 6.1 t (wood) | 6.1 t (coal) | 10,796 l (oil) |
Boiler
| Property | EC | EC1 | EC2 |
|---|---|---|---|
| Grate area | 4.051 m² | ||
| Firebox surface | 16.165 m² | 18.023 m² | |
| Tube heating surface | 173.079 m² | 172.428 m² | |
| Evaporative heating surface | 189.244 m² | 190.451 m² | |
| Superheater surface | 35.303 m² | ||
| Total heating surface | 224.5 m² | 225.8 m² | |
Power plant
| Property | EC | EC1 | EC2 |
|---|---|---|---|
| Driver diameter | 1,092 mm | ||
| Boiler pressure | 11.7 bar | 12.4 bar | |
| Expansion type | simple expansion | ||
| Cylinders | four, 419 x 559 mm | ||
Power
| Property | EC | EC1 | EC2 |
|---|---|---|---|
| Power source | steam | ||
| Estimated power | 820 kW (1,115 PS) | 969 kW (1,317 PS) | 1,044 kW (1,419 PS) |
| Starting effort | 179.1 kN | 189.6 kN | |
Calculated values
| Property | EC | EC1 | EC2 |
|---|---|---|---|
| Factor of adhesion | 1 : 4.42 | 1 : 4.67 | 1 : 4.63 |
| Optimal speed | 27 km/h | 34 km/h | |
| Power-to-weight ratio | 6.4 kW/t | 7.3 kW/t | 7.2 kW/t |
| Heating Surface Equivalent | 340.7 m² | 351.2 m² | |
| Cylinder volume/HSE | 1 : 905.11 | 1 : 878.05 | |
| Adhesive weight/Total | 1 : 1.58 | 1 : 1.56 | 1 : 1.61 |
| Tractive force/Heating surface | 1 : 16.65 | 1 : 17.54 | |
| Grate area/Heating surface | 1 : 55.43 | 1 : 55.73 | |
| Firebox/Tube surface | 1 : 10.71 | 1 : 9.57 | |
| Total/Superheater | 1 : 5.36 | 1 : 5.39 | |