Iphones losing time on Train .Strange 3G

Hello all, I work on a train that runs between New Orleans, La to Chicago, IL and the strangest thing has been happening. When going from Memphis, TN. To about Fulton, KY. everyone that has an iphone has been losing time. My phones alarm was set for 4:45 AM and good thing I woke up, because when I checked my phone it said 1:44 AM. It happened to me going North and coming South. It has also happen to some of my co-workers (about 6 others) that also have iphones. But not to anyone else non-iphones. I find this so strange! It happens only to iphones over the last two weeks. This has never happen before as Ive been on this route with my iphone for over 2 years. So now we cant depend on our iphones as alarms to wake us up. Does anyone have any ideas as to what is going on with our phones? Oh and after we get up the iphone will automatically reset to the correct time around 6:00 AM. Thanks
PC Windows 7