Original: Class 319 units have dual-power pick-up, from either 25 kV alternating current (AC) overhead lines for services north of London, or 750 V direct current (DC) third rail to the south.
Simplified: Class 319 units have dual power pick-up, from either 25 kV alternating current (AC) overhead lines for services north of London, or 750 V direct current (DC) third rail to the south.