Begin by flattening each steak to a roughly 1/4-inch thickness. To do so, place each piece between two sheets of heavy-duty plastic wrap and then flatten using a rolling pin or meat mallet.
In a large skillet, brown the now thin meat on both sides in the melted margarine. Drain off any excess fat, and then add the stewed tomatoes, sliced onion, celery, carrot, and Worcestershire sauce to the skillet. Cover the pan and then continue to cook over low heat for 1 hour and 15 minutes, or until the meat is tender. When cooked, transfer the meat to a serving plate, and keep warm.
After skimming any excess fat from the tomato mixture, combine the flour, salt, and water until well blended and then stir it into the tomato mixture. Cook the mixture over medium heat for about 2 minutes, stirring frequently, or until it has thickened and become bubbly.
Remove the sauce mixture from the heat, pour it over the meat, and serve immediately.