A liner panel for a combustor of a gas turbine engine includes a rail which at least partially defines an impingement cavity. The rail includes a notch which faces toward the impingement cavity. A method of cooling a wall assembly within a combustor for of a gas turbine engine includes directing air through a support shell and a liner panel to form a pressure drop across the support shell that is less than about 80% of a pressure drop across the combustor and to also form a pressure drop across the liner panel greater than about 20% of the pressure drop across the combustor.