Standardisation of locomotives
The Board has standardised most of its locomotive on one manufacture. The number of types from this manufacture were also strictly limited. The weight of a loco for hauling fuel trains is governed largely by the winter conditions of the temporary track on which the trains must run. For many years 7 tons was the weight limit and even this was achieved by using 2 tons of ballast which could be removed if track conditions could not carry the 7 ton loco. With improved track conditions over the years it is now possible to take a 9 ton locomotive on to a temporary track in milled peat bogs but here again provision has been made to reduce the weight, if necessary, to 7 tons by the removal of ballast.
To shunt a rake of wagons under a loading machine requires at times a very heavy pull at slow speed with plenty of sand under the loco wheels. On the other hand, when the train is on the level main lines with runs of up to 12 miles (19 km), a fast, lively locomotive is required. In an attempt to meet a balance between these two needs an 80.h.p. locomotive was designed.