50 kV Electrification of the Tumbler Ridge Branch Line Conceptual Design

The new 130 km long Tumbler Ridge Branch Line of the British Columbia   Railways will serve to haul coal from the Northeast Coal Block in the Province of British Columbia. Economic studies comparing diesel with electric traction resulted in the decision to electrify this new branch line at a voltage of 50 kV from catenary to rails. Due to the absence of high voltage transmission facilities along the line, there will be only one substation feeding the catenary located near the eastern end of the branch line. With 13,000 tonne unit trains and a compensated grade of 1.2% in the direction of loaded trains, the single ended supply to the catenary required the insertion of a series capacitor half way along the line in addition to providing a 50 kV feeder parallel with the contact system. The paper describes the choice of the conductors forming the overhead contact system, the single line diagram of the Tumbler Ridge, 230/50 kV trackside substation and considerations leading to the series capacitor station. Power factor correction, harmonic filtering and supervisory control facilities are briefly discussed.