By 1984 the passenger trains in intrastate services had either self contained power supplies or were set up for Head End Power. The N and P class locomotives had HEP generators for use on these trains.
In the event of HEP sets being hauled by non-HEP locomotives, three freight vans were fitted with generator sets and suitable cables in 1984. The corrugated roofs were replaced by sheet metal. The vans were coded PH and numbered 451, 452 and 453. They were converted from VLPY 139, 140 and 142 respectively.