Combine Worcestershire sauce and vinegar in a medium bowl. Add roast beef, and toss to combine.
. Combine mayonnaise, chopped sun-dried tomato, and blue cheese in a small bowl; stir well. Spread about 1 1/2 tablespoons mayonnaise mixture on each of 4 bread slices. Top evenly with roast beef, lettuce, tomato, and remaining bread slices.