Development of Material for Train Overhead Contact Wire
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Date
2015-05
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Addis Ababa University
Abstract
This paper presents the development of material for train overhead contact wire. In view of the
current Addis Ababa Light Rail Train overhead contact wire with high material cost and low
wear resistance ; the copper alloys which has better mechanical wear and corrosion resistance
with moderately low cost, are developed. The mechanical properties and electrical conductivities
of the prepared copper alloys were investigated by using lab testing machines. Wear tests were
conducted by a pin- on-disc Tribometer which simulated the tribological conditions of sliding
contact strip on overhead wires in the railway system. The copper-alloys in the form of
cylindrical pins were forced to slide against a stainless steel disc with a sliding velocity of 80
km/h at room temperature under unlubricated condition and normal load up to 11N without
electric current. In addition to this, the electrical conductivity of the copper alloys were
investigated by multimeter . Among the alloys investigated, CuNiCr, which possesses quite
good electrical conductivity and relatively high wear resistance (2 times that of Cu Ag)
.Also in order to simulate costal and acidic environment, corrosion test is conducted in acid rain,
salt solution and in distilled water. The corrosion from the specimens was studied by weight loss
measured by analytical balance among the copper alloys Cu Ag is highly corroded and worn
surfaces of the copper alloys pin were analyzed by optical microscope from these parallel and
continuous scratches in the direction of motion observed. From this experimental investigation
the dominated wear mechanisms are abrasive and adhesive wear in mechanical sliding frictional
process. Finally the cost analysis of copper alloys per each pin performed and Cu- Ni -Cr takes
less cost from others. By considering wear resistance, corrosion resistance, electrical
conductivity and cost, Cu Ni Cr is appropriate for Addis Ababa light rail train and future national
railway overhead line contact wire.
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Keywords
Train Overhead Contact Wire, Addis Ababa Light Rail Train, Material