1,100 sections of the line, varying from collapsed station roofs to bent power pylons, would need repairs. Services on the Tōhoku Shinkansen partially resumed only in Kantō area on 15 March, with one round-trip service per hour between Tokyo and Nasu-Shiobara, and Tōhoku area service partially resumed on 22 March between Morioka and Shin-Aomori. Services on Akita Shinkansen resumed with limited numbers of trains on 18 March. Service between Tokyo and Shin-Aomori was restored by May, but at lower speeds due to ongoing restoration work; the pre-earthquake timetable was not reinstated until late September. The rolling blackouts brought on by the crises at the nuclear power plants in Fukushima had a profound effect on the rail networks around Tokyo starting on 14 March. Major railways began running trains at 10–20 minute intervals, rather than the usual 3–5 minute intervals, operating some lines only at rush hour and completely shutting down others; notably, the Tōkaidō Main Line, Yokosuka Line, Sōbu Main Line and Chūō-Sōbu Line were all stopped for the day. This led to near-paralysis within the capital, with long lines at train stations and many people unable to come to work or get home. Railway operators gradually increased capacity over the next few days, until running at approximately 80% capacity by 17 March and relieving the worst of the passenger congestion. Telecommunications Cellular and landline phone service suffered major disruptions in the affected area. Immediately after the earthquake cellular communication was jammed across much of Japan due to a surge of network activity. On the day of the quake itself American broadcaster NPR was unable to reach anyone in Sendai with a working phone or access to the Internet. Internet services were largely unaffected in areas where basic infrastructure remained, despite the earthquake having damaged portions of several undersea cable systems landing in the affected regions; these systems were able to reroute around affected segments onto redundant links. Within Japan, only a few websites were initially unreachable. Several Wi-Fi hotspot providers reacted to the quake by providing free access to their networks, and some American telecommunications and VoIP companies such as AT&T, Sprint, Verizon, T-Mobile and VoIP companies such as netTALK and Vonage have offered free calls to (and in some cases, from) Japan for a limited time, as did Germany's Deutsche Telekom. Defense Matsushima Air Field of the Japan Self-Defense Force in Miyagi Prefecture received a tsunami warning, and