The Challenge For Softech
Transport for London’s Four Lines Modernisation (4LM) programme sought to replace over a century-old fixed-block signalling system with a modern Communications-Based Train Control (CBTC) moving-block system across the Circle, District, Hammersmith & City and Metropolitan lines. The principal challenge was delivering this transformation on one of the world’s busiest metro networks while maintaining passenger services. Migration activities had to be carefully planned within limited overnight engineering possessions, requiring integration between the legacy and CBTC systems, meticulous staging and robust rollback arrangements to minimise operational disruption and maintain railway safety.
Softech’s Solution
As part of the wider Thales delivery team, Softech Rail engineers contributed to the development of CBTC signalling designs, installation methodologies, migration plans and implementation strategies for the phased introduction of the new signalling system. Our engineers prepared engineering documentation, installation sequences and migration activities for execution during the four-hour overnight engineering window. They also supported site implementation, testing coordination and rollback planning, helping to ensure each migration phase was completed safely while minimising disruption to passenger operations.
Feedback
Dean Ford
“Engineers assigned to tasks performed to a very high standard and were professional in approach. Would not hesitate to seek support from Softech on any potential future requirement.”


















