More than 18,000 subway riders used new late-night service on the MBTA last weekend during the first two nights of the yearlong pilot program, the T announced Tuesday.

The MBTA recorded 18,372 entries into the subway system between 12:30 a.m. and 3 a.m. early Saturday and early Sunday. Fifty-nine percent of the people entering the T during those hours used a station in downtown Boston. More than 1,000 entries were recorded at six stations: Park, Harvard, Haymarket, Central, Kenmore and Downtown Crossing.

(Eric Kilby/Flickr via Compflight)

The Red and Green lines each recorded more than 5,000 riders over the weekend. The Blue Line saw the fewest riders.

"We're off to a very good start," MBTA General Manager Beverly Scott said in a statement. "Let's keep it going!"

The new program provides service until about 3 a.m. on all four T subway lines and 16 heavily traveled bus routes. It is the MBTA's most recent attempt at late night service; its "Night Owl" bus-only service was canceled in 2005.

An MBTA spokesman said ridership numbers for above-ground Green Line service and bus lines will be released later in the week.