Bork and two of the track's owners, Keith Wagner and George Yeatras, signed the papers Wednesday afternoon at the law offices of Bowles, Rice, McDavid, Graff and Love in Martinsburg.
Officials originally had expected Penn National to take over the track by December, but the move was delayed, in part by a federal suit.
Despite Penn National's plan to install video lottery at the track, a Deleware firm known as GTECH claimed that an agreement it signed more than two years ago gave it the sole right to place the machines at the track, according to a suit filed in U.S. District Court in Martinsburg.
GTECH had requested a preliminary injunction barring Penn National from buying the track unless Penn National accepted the agreement.
But District Court Judge W. Craig Broadwater denied GTECH's request, saying there was little indication that the track would not honor the agreement.
Despite the delays, Bork said Penn National plans to reopen the track by April 1. Major work on the renovation of the track will begin in about two weeks, said Bork.
Bork said Peter Carlino, chairman of Penn National, was at the track Wednesday with an architect and engineer.
"Tomorrow there will be some activity there," said Bork.
Penn National plans to make extensive improvements at the track, including razing Shenandoah Downs and building new barns. In order to complete the renovations, track officials said they would have to lay off about 400 track workers until spring.
Penn National promised to purchase the track if Jefferson County voters passed video lottery in the general election in November. The games sailed to victory in the election.
Track officials said if voters did not approve the games, the struggling oval would close. Attendance and wagering had steadily declined at the track, and Penn National officials said last March that they didn't know if the track could survive until the end of the year.