EPC Services have just completed designs for fifty seven transformer rectifiers replacements in thirty seven locations on the Network Rail DC traction system.  This involved integration of new equipment into substations with older equipment installed and presented a number of technical challenges. The programme represented the largest number of transformer rectifier units installed on the  system in the past 2-3 years. With our partner EDF Energy this installation was conducted in the shortest possible timescale whilst ensuring safety and operational performance of the system was maintained.