Your look at the five biggest and most buzz-worthy stories of the morning.
1. Metro-North Train Was Speeding When It Derailed
The New York Metro-North train that derailed over the weekend killing four people was going 82 mph as it entered a 30 mph curve, a federal investigator said.
2. New Obamacare Headache: Is Your Enrollment Real?
Obama administration officials acknowledged that some of the roughly 126,000 Americans who completed the Healthcare.gov enrollment process in October and November might not be officially signed up with their selected issuer, even if the website has told them they are.
3. Scientists Find Aggressive New HIV Strain
Swedish scientists have identified a new strain of HIV that appears to progress much faster than most previously identified variations of the virus.
4. Iran Doesn't Want Afghanistan to Sign US Deal
Iran's foreign ministry asked Afghanistan not to sign a security deal with the U.S. that could keep American and allied forces in its neighboring country for another decade.
5. Bitter Cold Weather Hits US
Thirteen states from California to Wisconsin are under winter weather warnings as the coldest air in 16 years for some states sweeps through the U.S.