Tutor Perini Corp. announced Thursday a subsidiary has won a $510 million contract at the Hudson Yards mixed use development in downtown New York City.

The Sylmar construction firm will build a platform structure in conjunction with Related Cos. and Oxford Properties Group on the project.

The platform will be made of structural steel frame with a reinforced concrete deck. It will bridge the active Long Island Rail Road eastern rail yard and serve as the foundation for future buildings at Hudson Yards.

Construction of the platform has already started and will be completed by 2016. The platform construction will be coordinated with Tutor Perini’s work already underway on the Amtrak concrete tunnel box at the same site.

The company has previously been awarded two large contracts at Hudson Yards, a 26-acre site slated for 6 million square feet of commercial space, 5,000 residences, a public school and luxury hotel.

Shares closed up 5 cents, or less than 1 percent, to $25.52 on the New York Stock Exchange.