Transit authorities planning to transition from conventional to CBTC signaling must treat the depot and mainline as a single entity; otherwise the boundary becomes a barrier for launching trains into service. The barrier results from CBTC and conventional signalling speaking different languages; a simplified interface will lose something in translation, preventing a seamless handover of a train from depot to mainline.
Transit agencies planning to deploy a CBTC solution must be mindful that a CBTC solution is effective only when it has control over all aspects that affect mainline operations. The time it takes to launch trains from the depot is also a factor because it compromises the throughput on the mainline. Non-CBTC actors, such as a conventionally signalled depot, hinder a CBTC solution’s ability to control the flow of trains on the mainline, reducing the advantages CBTC was meant to introduce.
Implementing a CBTC solution on the mainline and leaving the depot conventionally signalled is a mistake.