A sprocket segment for a sprocket used to drive a track chain assembly, comprising: a body including at least partially a cylindrical configuration defining a circumferential direction , a radial direction , and an axis of rotation , the body including a radially inner portion that extends in the radial direction and in the axial direction , the radially inner portion defining an inner axial width of the radially inner portion , and an inner radial height of the radially inner portion ; and a radially outer portion that extends along the axial direction and the radial direction , defining an outer axial width of the radially outer portion , and an outer radial height of the radially outer portion , the outer axial width of the radially outer portion being greater than the inner axial width of the radially inner portion , the radially outer portion also including an outer undulating circumferential surface (318', 418'm 518'); wherein the radially outer portion further defines an inner cylindrical circumferential bearing surface disposed axially on one side of the radially inner portion , and a first wing extending axially from the radially outer portion that is disposed radially and axially adjacent to the inner cylindrical circumferential bearing surface , the first wing defining a first wing radial height that is less than the outer radial height of the radially outer portion , the radially outer portion also defining a plurality of cut-outs extending radially through the radially outer portion disposed axially on the other side of the radially inner portion relative to the first wing ; characterised in that the radially inner portion defines a plurality of fastener receiving holes extending axially through the radially inner portion and the radially outer portion includes at least two keys extending axially and radially inwardly from the inner cylindrical circumferential bearing surface . a body including at least partially a cylindrical configuration defining a circumferential direction , a radial direction , and an axis of rotation , the body including a radially inner portion that extends in the radial direction and in the axial direction , the radially inner portion defining an inner axial width of the radially inner portion , and an inner radial height of the radially inner portion ; and a radially outer portion that extends along the axial direction and the radial direction , defining an outer axial width of the radially outer portion , and an outer radial height of the radially outer portion , the outer axial width of the radially outer portion being greater than the inner axial width of the radially inner portion , the radially outer portion also including an outer undulating circumferential surface (318', 418'm 518'); wherein the radially outer portion further defines an inner cylindrical circumferential bearing surface disposed axially on one side of the radially inner portion , and a first wing extending axially from the radially outer portion that is disposed radially and axially adjacent to the inner cylindrical circumferential bearing surface , the first wing defining a first wing radial height that is less than the outer radial height of the radially outer portion , the radially outer portion also defining a plurality of cut-outs extending radially through the radially outer portion disposed axially on the other side of the radially inner portion relative to the first wing ; characterised in that the radially inner portion defines a plurality of fastener receiving holes extending axially through the radially inner portion and the radially outer portion includes at least two keys extending axially and radially inwardly from the inner cylindrical circumferential bearing surface . <EOS>