just found this at Amtrak's website. Hope this doesnt affect too many on the Autotrain. 
Amtrak Service South of Washington Disrupted by Freight Derailment
Amtrak service south of Washington, DC has been disrupted by the derailment of a CSX coal train at Quantico, Va. The railroad is shut down at Quantico with all tracks blocked.
All Amtrak trains that were stopped en route are presently located at Amtrak stations located from Washington to Richmond. Announcements are being made to alert passengers of the situation.
A number of Amtrak trains are cancelled. Amtrak is attempting to secure alternate transportation, but it is expected more than 2300 passengers will be affected throughout the evening.
Additional updates will be issued as new information becomes available.
Amtrak regrets any inconvenience. This information is correct as of the above time and date. Information is subject to change as conditions warrant. Passengers are encouraged to call 800-USA-RAIL or visit Amtrak.com for schedule information and train status updates.

Amtrak Service South of Washington Disrupted by Freight Derailment
Amtrak service south of Washington, DC has been disrupted by the derailment of a CSX coal train at Quantico, Va. The railroad is shut down at Quantico with all tracks blocked.
All Amtrak trains that were stopped en route are presently located at Amtrak stations located from Washington to Richmond. Announcements are being made to alert passengers of the situation.
A number of Amtrak trains are cancelled. Amtrak is attempting to secure alternate transportation, but it is expected more than 2300 passengers will be affected throughout the evening.
Additional updates will be issued as new information becomes available.
Amtrak regrets any inconvenience. This information is correct as of the above time and date. Information is subject to change as conditions warrant. Passengers are encouraged to call 800-USA-RAIL or visit Amtrak.com for schedule information and train status updates.