I would appreciate if others let me know if this is a commonly observed problem: I am out of network every day when I take the metro-rail. When I get back to having network, my iPhone 5 (Firmware: 1.00.16) takes 5-20 minutes to receive signal. I have deduced this since I typically have to wait for this time before my mailbox loads new mails or before I can successfully open a link using Safari. Please let me know if this is a common problem and if anything can be done to fix it. Thank you!