Straphangers hoping to get from one end of the G line to the other Wednesday night will need to take three trains, as work crews shut down a track in central Brooklyn to plug an underground leak. Repairs to a leaky water pipe along the Crosstown Line will require the closure of one of the two tracks between the Hoyt-Schermerhorn and Bedford-Nostrand stations, MTA spokeswoman Meghan Keegan told the Daily News. Starting at 11:30 p.m. on Wednesday, the G train will operate in multiple segments, running as usual from the Court Square station in Long Island City, Queens, to the Bedford-Nostrand Ave. station in Bed-Stuy. The one open track between Bedford-Nostrand and Hoyt-Schermerhorn will carry trains in both directions while repair work is being done — with service every 20 minutes. G train service will not continue along the Culver Line beyond Hoyt-Schermerhorn, and passengers wishing to travel further south will have to get on the F train at the nearby Bergen St. station. Keegan said the repair is expected to be straightforward and shouldn’t take more than one night. Full service on the G train is expected to resume by 5 a.m. on Thursday. The exact cause and location of the leak wasn’t immediately clear. The MTA recently wrapped up a major overhaul of the Crosstown Line, which carries the G from Hoyt-Schemerhorn St. to Court Square. That work, which shut down service on portions of the line in July and August, saw the installation of nearly 600,000 feet of wire in anticipation of modern computerized signaling. Six signal relay rooms and 17 switches — all north of the current leak — were also modernized during the summer outage.