On March 22, Tokyo Metro announced new diagrams with the begining of through service between Tokyu Line and Fukutoshin Line from March 16.
During daytime from 10a.m to 4p.m, express train(Limited Express train on Tokyu Toyoko Line) will run between Ikebukuro and Yokohama for 38 mins at 15-minute intervals. In addition to it, Total travel time will also be shortened by 10 mins.
Fukutoshin Line has already begun through service to Tobu Tojo Line and Seibu Yurakucho・Ikebukuro Lines, which are in Western Saitama. After the connection with Tokyu Toyoko Line, passengers will be able to take only one train from Shinrin Koen to Motomachi・Chinatown. The total distance is 88.6 km.
By March, Tokyo Metro expects that 440 thousands people will be users of Fukutoshin Line everyday. The number is larger than that of conventional users by 100 thousands. Therefore, another 40 local trains are going to be added to the Line.
Citation: http://www.asahi.com/travel/rail/news/TKY201301220396.html
A problem of through service is that train delay spreads over whole lines. I'm interested in how companies involved solve the problem.
