Set oven control to broil. In small bowl, mix mayonnaise and mustard. Place toasted bottom halves of bagels on ungreased cookie sheet. Spread each with mayonnaise mixture. Top each evenly with turkey, ham and cheese.
Broil 4 to 6 inches from heat 2 to 3 minutes or until cheese is melted. Top each with tomato slice and toasted top half of bagel. Wrap each sandwich securely with foil; take with you for an on-the-go dinner.