The 3000-volt mercury-arc-rectifier traction substations of the South African Railways

The paper gives a brief description of the electrified sections of the South African Railways and the general details of the mercury-arcrcctifier traction substations provided on the different sections. The reasons are given for the decision to use inverters and rectifiers with grid control for compounding on the extensions to the electrified sections in Natal. Reference is also made to the type of plant selected for the new projects. The characteristic curves for the different types of plant are submitted, and the advantages and disadvantages are indicated. The difficulties which have been experienced under service conditions and the remedial measures taken are discussed.