Abstract: The present invention provides a rail weld treatment device for improving a resulting microstructure in and around an effected zone of a rail weld and of rails surrounding the rail weld. The device includes, but is not limited to a fixture clamping and centering assembly for engaging a rail head of a rail and a heating and cooling device connected with the fixture clamping and centering assembly to be positioned over the rail head. The fixture clamping and centering assembly comprises an engagement member which removably engages the rail head. The heating and cooling device includes a heating member for heating an effected zone of the rail weld and a cooling member for cooling the effected zone.