sentences:  Units 9032, 9033 and 9034 were modified by EDi Rail in May 2017 to increase their mass to 177 tons, bringing their tractive effort on par with more modern AC units.Restricted to the Hunter Valley the 90 class operate on the Main Northern line as far as the Dartbrook, and on Ulan on the Gulgong line.They have also operated as far south as Eraring Power Station at Dora Creek.