A device for damping of vibratory energy in turbine blades of rotor assemblies during operation, comprising: a first turbine blade having a first shroud, a first upstream rail extending radially outward from the first shroud and a first downstream rail extending radially outward from the first shroud, each rail extending across the top surface of the first shroud between first and second circumferential sides of the respective rail, wherein the first upstream rail is a first sealing rail, a second turbine blade adjacent the first turbine blade and having a second shroud, a second upstream rail extending radially outward from the second shroud and a second downstream rail extending radially outward from the second shroud, each rail extending across the top surface of the second shroud between first and second circumferential sides of the respective rail, wherein the second upstream rail is a second sealing rail, characterised in that the first sealing rail has a generally circumferential slot extending into each circumferential side of the first sealing rail; the second sealing rail has a generally circumferential slot extending into each circumferential side of the second sealing rail; a first slot of the generally circumferential slots at a first circumferential side of the first sealing rail nearest the second turbine blade is adjacent and opposing a second slot of the generally circumferential slots at a circumferential side of the second sealing rail nearest the first turbine blade; and a damper element is positioned in and extends between the first and second slots; wherein the slots at the circumferential sides of the first and second turbine blades (14a, 14b) are positioned between the shroud (17a, 17b) and a radially outer surface of the first and second sealing rails (19a, 19b) to keep the damper element out of the flow of gas; and wherein the damper element is generally "U" shaped and comprises a flat center portion, a first side portion and a second side portion, and wherein the flat center portion engages end faces of the slots and the side portions of the "U" extend radially up or down along axial sides of the first and second sealing rails (19a, 19b) having the slots. a first turbine blade having a first shroud, a first upstream rail extending radially outward from the first shroud and a first downstream rail extending radially outward from the first shroud, each rail extending across the top surface of the first shroud between first and second circumferential sides of the respective rail, wherein the first upstream rail is a first sealing rail, a second turbine blade adjacent the first turbine blade and having a second shroud, a second upstream rail extending radially outward from the second shroud and a second downstream rail extending radially outward from the second shroud, each rail extending across the top surface of the second shroud between first and second circumferential sides of the respective rail, wherein the second upstream rail is a second sealing rail, characterised in that the first sealing rail has a generally circumferential slot extending into each circumferential side of the first sealing rail; the second sealing rail has a generally circumferential slot extending into each circumferential side of the second sealing rail; a first slot of the generally circumferential slots at a first circumferential side of the first sealing rail nearest the second turbine blade is adjacent and opposing a second slot of the generally circumferential slots at a circumferential side of the second sealing rail nearest the first turbine blade; and a damper element is positioned in and extends between the first and second slots; wherein the slots at the circumferential sides of the first and second turbine blades (14a, 14b) are positioned between the shroud (17a, 17b) and a radially outer surface of the first and second sealing rails (19a, 19b) to keep the damper element out of the flow of gas; and wherein the damper element is generally "U" shaped and comprises a flat center portion, a first side portion and a second side portion, and wherein the flat center portion engages end faces of the slots and the side portions of the "U" extend radially up or down along axial sides of the first and second sealing rails (19a, 19b) having the slots. a damper element is positioned in and extends between the first and second slots; wherein the slots at the circumferential sides of the first and second turbine blades (14a, 14b) are positioned between the shroud (17a, 17b) and a radially outer surface of the first and second sealing rails (19a, 19b) to keep the damper element out of the flow of gas; and wherein the damper element is generally "U" shaped and comprises a flat center portion, a first side portion and a second side portion, and wherein the flat center portion engages end faces of the slots and the side portions of the "U" extend radially up or down along axial sides of the first and second sealing rails (19a, 19b) having the slots.