Manassas line update

NS maintainer will not be able to clear tracks for another half hour. 338 will return to the yard and will be cancelled. Train 335 will also be cancelled. 335 will hold at Alexandria and run on 337's schedule. Passengers at Union Station, L'Enfant and Crystal City who need to ride 337 will need to catch Fredericksburg train 315, detrain at Alexandria and transfer to Manassas 337.