Metro closed its rail system an hour earlier than it said it would Sunday amid the change back to standard time, leaving late-night riders stranded.

The transit agency alerted riders with a special statement Friday that it would give them an extra hour of service, running trains until 3 a.m. Eastern Standard Time, even though clocks were turning back at the end of daylight saving time. Normally, the system stays open until 3 a.m. every Friday and Saturday into Sunday.

But over the weekend, the agency actually closed down at 3 a.m. Eastern Daylight Time, meaning 2 a.m. Eastern Standard Time.

The agency realized it made the mistake early Sunday morning and contacted WTOP. The radio station tweeted out a message at 2:11 a.m. But an untold number of riders had not see it in time and found closed stations before the 3 a.m. purported closing. Some of them grumbled on Twitter as they found locked gates.

The transit agency acknowledged the mistake Monday afternoon on Twitter in two tweets.

"We made a mistake in our closing time Saturday night & we apologize to our customers for any inconvenience," the agency wrote on its @wmata account. "The system closed at 3 a.m. EDT when it should have closed at 3 a.m. EST. Our deepest apologies to customers."

It was not immediately clear why Metro had the confusion between its left-hand operations and its right-hand communications team. It typically offers an hour of extra service for the fall time change and an hour less for the spring change.

The transit agency had similar scheduling challenges earlier this fall when a top official said the agency was scheduling a Rush Plus promotion effort specifically to avoid the Jewish high holidays, Rosh Hashanah and Yom Kippur. But Metro then canceled the promotion without telling anyone on the first day it was supposed to occur, amid Rosh Hashanah. The agency later said the four-day campaign was called off because it actually fell during the two holidays.