Paragraph 34 Particulars of the Barriers and Other Protective Equipment when the Road is Open to the Public.

Two independent power supplies shall be provided at the crossing, one of which may consist of batteries. In the event of a mains power supply failure the capacity of the batteries shall be sufficient to operate the railway approach intermittent signals mentioned in paragraph 31 above for a duration of not less than 48 hours and also to operate both barriers to the fully raised position.