The urban and mass transit industry has a number of special requirements, all related to the challenge of a system that must handle extremely high train density 24/7. Particular emphasis must be placed on having maximum uptime and reliability of all components in a train control system. Because metros must support frequent and continuous operation, often in difficult environmental conditions, reliable equipment is essential to sustain operational availability.
System availability can be significantly impacted by maintenance considerations, in particular the mean time to repair. The less time required for maintenance the better, especially in the case of corrective maintenance which can interfere with scheduled operations during the repair cycle. The ideal train control system should deliver the dual benefits of maximum uptime combined with maximum cost-efficiency.