A fire caused major delays earlier this week. And last year, a similar incident caused a train to fill with smoke in a tunnel, killing one passenger.
City officials feared the closure would cause major disruption in the US capital, but the expected commuting nightmare failed to materialise.
Washington’s bike-sharing programme offered free 24-hour memberships and buses and streetcars saw increased ridership.
Washington’s Metro, the second busiest subway system in the US, will reopen on Thursday after an unprecedented all-day shutdown over safety concerns.
A series of electrical fires led to the system-wide shut down as workers spent Wednesday inspecting power cables.
Traffic increased significantly on the city’s roads, but police reported only minor accidents.
The federal government encouraged employees to work from home, but local schools remained open.
