Complex sentence: Tramlink route 5 is the only extension being formally developed, linking Harrington Road with Crystal Palace, and Crystal Palace with Beckenham Junction, both terminating at Crystal Palace Parade.
Split into simpler sentences: Tramlink route 5 is the only extension being formally developed. The proposed route links Harrington Road with Crystal Palace, and Crystal Palace with Beckenham Junction, both terminating at Crystal Palace Parade.