Traction and Vehicle Types

As key aims of the railway include reducing the dependency on oil and improving the environment, electric traction is certainly to be considered. For Ethiopia, the relative costs of imported oil and domestically‐produced hydro‐electricity tilt the balance firmly in favour of electrification, and this was recognised in the Government’s long‐ term strategy for the railways. However, electric traction brings higher capital and maintenance costs (e.g. of overhead line equipment (OHLE)) and, in order for this to be cost‐effective, its costs need to be spread across a reasonably‐large number of train movements e.g. at least 1 per hour. Whilst this will undoubtedly be the case for the area around Addis Ababa, this is less the case for more distant areas.

Whole‐life cost analysis of the NRNE programme suggests that electrification between Mojo and Hawassa should be undertaken as part of the initial project construction. However, the most cost‐effective policy may be to use the diesel locomotives, which will be required for construction phases, on service trains (passenger and freight) on the fringes of the network, until such time as electrification is provided in these areas.

Historically, railways followed a policy of common‐user motive power, with locomotives hauling either passenger or freight services. In more recent years, however, the requirements of freight and passenger have diverged somewhat, with freight locomotives needing higher tractive effort and passenger locomotives higher speed, two characteristics which are not readily‐compatible. The exception might be on some of the more distant branch lines, where service frequencies are very low and where trains might carry both passenger and freight traffic.

Self‐propelled multiple‐unit trains have become popular for passenger operations, partly because they enable quicker turn around at turn back or terminal stations. However, having most if not all vehicles motorised becomes less and less efficient as trains get longer, as equipment has to be replicated. This is perhaps less of an issue with electric traction, since motors are lighter and fuel does not have to be carried round. Nevertheless, as there is some doubt about the initial level of demand, and because passengers respond positively to service frequency, the operation of multiple‐unit trains on at least some services would appear to be appropriate. ‘Outer‐suburban’ services in the greater Addis region would be a sensible use of such trains.

Multiple‐unit trains can be helpful if trains are to join/split en route (goods collecting trains), which can be an efficient method of operation; these principles could be applied along the whole 2^nd corridor. Alternatively, smaller trains which stop at all stations can follow larger inter city type trains which serve only the major towns along the route.

On the freight side, the wagons required need to reflect the types of traffic expected. However, there is a trade‐off to be made between a plethora of specialist wagons (each of which will require maintenance, technician training, spare parts and spare wagons) and not being able to carry some goods because of a lack of appropriate wagons.

Information on location and size of industrial plants is currently being gathered and a better assessment as to how this will impact capacity and revenue aspirations will be set out in the detailed feasibility report for this line.

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