The signalling system from Southease to the North (Southerham Junction) and to the South (Newhaven) had recently been modernised and control transferred to Three Bridges Rail Operations Centre. The signalling power supplies in the area remained largely unaltered.

The existing Southease substation supply arrangement feeds locations LW51-LW42 which consists of a total of 9 equipment housings at 440V. The supply equipment within Southease substation is old and beyond repair.

Network Rail issued a remit to alter the feeding arrangements to facilitate the removal of the life expired 440v feeder at Southease and to re-supply the locations at 650v from an existing Lewes substation power pillar feeder.

The design included the following:

• Provision of new 650/110v FSP Enclosures, transformers, switchgear and cables at LW42, LW43, LW44, LW45, LW46 & LW51 Location cases.
• De-commissioning and removal of all redundant equipment including cabling from Southease Substation through to LW42 Location.
• Provision power loading calculations, the update to existing records, test records and certificate of installation, including update records of the signal supply power/cable schematic and layout drawings if available.

All designs complied with the functionally equivalent design process using forms A to E as specified in Signal Design Handbook Module A2-9.