The Wirral line was operated on the third rail system but the Mersey Railway system was on fourth rail, so the new trains were fitted with negative contact shoes and a contactor which was automatically operated according to the system. This was considered to be a cheaper option than installing a fourth rail throughout the new Wirral electrified area. There was a 50-foot gap in the conductor rails at each end of the Birkenhead Park station: the only such changing point on any British Railway.