You can take a train from Union station to cumberland. And I believe those run daily on amtrak.

http://tickets.amtrak.com/Amtrak/sid=03E8B23588AFFDE726D13313DA81DD06/availability?storefront=1003&pageID=main

It's exactly 1.5 hours from Cumberland to CV by car if you obey speed limits.

Has anyone actually tried taking the train to Cumberland , and then renting a car and driving to CV or Deep Creek? If so, was it worth it?

Train 29
Washington-Union Station Cumberland 03/12/04
5:20pm 03/12/04
8:29pm

30
Cumberland, MARYLAND (CUM) Washington-Union Station, DISTRICT OF COLUMBIA (WAS) 8:47am
03/15/04
12:24pm
03/15/04

www.amtrak.com

The 1 way fare is $61 RT--not bad, but you still need to get from Cumberland to Canaan Valley.