Conservation law, also called law of conservation, in physics, several principles that state that certain physical properties (i.e., measurable quantities) do not change in the course of time within an isolated physical system. In classical physics, laws of this type govern energy, momentum, angular momentum, mass, and electric charge.
On New Yearâs Eve, the Metrorail system will open at 7 a.m. with special extended service on all lines until 3 a.m. The additional three hours of service â consistent with past years â is a special exception to a moratorium on extended hours during the year-long SafeTrack maintenance program.
Train service stops around midnight Sunday through Thursday and 3:00 a.m. on Fridays and Saturdays. However, the last train sometimes leaves before the closing time. According to the Metro page, the last train leaves for Fort Totten (Yellow Line) at 11:44 and Largo (Blue Line) at 11:47.