Food trucks - one a day for now - are setting up for lunch behind the building at 990 Spring Garden St., in the emerging section of town near Union Transfer that soon will become home to Viaduct Rail Park.

Hours will be 10 a.m. to 2 p.m. Wednesdays, Thursdays, and Fridays.

The premiere, Wednesday, April 6, will feature the debut of Hai Street Kitchen & Co.'s food truck. Hai Street, with physical locations at 32 S. 18th St. and 125 S. 40th St., offers burritos fashioned sushi-roll style. The initial offerings will be the chicken roll, flaming' tuna roll, Ho-Lee shrimp roll, So Cal roll, and Philly Roll (including salmon, cream cheese, spring mix, cucumber, pickled red onion).

Thursday, April 7's truck will be Wahlburgers, while Friday, April 8's will be Oink & Moo.

The building at 990 Spring Garden, now home of a few city offices, is being converted into loft-style suites to attract new companies and tech firms.  The arrangement is between the building management and the Philly Mobile Food Association.