ABSTRACT
For any metro operator the decision to modernize an existing signaling system can be dictated by various parameters including improvement of performance, energy saving, obsolescence management and so on.
Modification of an existing system always remains a challenge and no disruption to revenue service during the migration is allowed even when the interfaces with operation and maintenance are complex and only short periods of work are possible on site during the night.
The Migration strategy is the key sequence of actions for the transition from an existing operational signaling system to a new operational signaling system without disruptions and at minimum cost. This migration strategy is specific to each project. But success of the migration will depend for a part on the proposed technology. A flexible solution such as a CBTC can facilitate the migration thanks to its facility to be overlaid on an old signaling system with a minimum of interference. It still requires the extended use of factory testing and a powerful simulator, the use of formal software development and proof to minimize errors, and a product approach covering both system and deployment aspects. But these factors alone are not sufficient. Success always depends on the possibility to work closely with the customer/operator teams, to determine together how to best deploy the technology, to focus on installation and commissioning issues, to deal with operations and operations change-over issues.
All Alstom’s recent migration projects on major metros represent the state-of-the-art in non-disruptive migrations. They have been successfully implemented thanks to the URBALIS CBTC delivery-oriented process and flexible architecture.
