An investigation into current collection problems in clapton tunnels (ER) (TM-ES-031)

1. INTRODUCTION 1.1 Background In preparation for the changeover from 6.25 kV to 25 kV supply voltage, the overhead line equipment in Clapton Tunnels on the Eastern Region was modified to give increased electrical clearances. Within days, severe arcing and flashovers at the 40 mile/hr line speed necessitated...