Heat oven to 450°F; foil-line 18-by-13-inch rimmed metal sheet. Toss potatoes with 1 tablespoon oil, rosemary, and 1/4 teaspoon salt; roast 20 minutes.
Pat steak dry; rub with Worcestershire, garlic powder, pepper, 1 teaspoon oil, and 1/4 teaspoon salt. Toss beans with remaining oil and salt.
Turn potatoes; add beans and roast 7 minutes more. Move vegetables to edges; lay steak flat in center.
Switch to broil, pan about 6 inches from element. Broil steak 4 to 6 minutes per side to 145°F, watching vegetables and turning dark pieces inward.
Transfer steak to clean board; rest at least 3 minutes, preferably 5. Thinly slice across grain; serve with potatoes and beans.