Signalling system switch-over and Interoperability implementation without Suspension of the Train service (Seoul Line No.2 Signalling system refurbishment)

열차 운행의 중단없는 신호시스템 절체 및 병행운전 구현 (서울 2 호선 신호설비 개량)

The Seoul subway line No.2 is the one of the busiest metro service line of the passenger transportation in Seoul metropolitan city. The number of the passengers served by the Seoul subway line No.2 is more than 1.9 million in a day according to the transportation reference of 2004, which is about $15\%$ of the whole population in Seoul metropolitan city. This is the reason why the Seoul Metropolitan Subway Corporation(SMSC) is implementing the refurbishment of the current ATS signalling system of Seoul Line No.2 into the most advanced ATO system with the continuous air-gap telegram transmission through the track circuit without any suspension of the train service either in when or in where, which is the first in the world in its attempt to refurbish the old signalling system under service without any suspension of the train operation.