 As early as July 1951 the Victorian Minister for Transport announced that the remaining 28 X class locomotives were to be converted to PBC operation.Victorian Railways went on to convert express passenger locomotive R707 to PBC operation and went as far as placing tenders for the construction of a further 15 new brown-coal fired X class locomotives.However, by 1957 the price of PBC had doubled against a fall in the price of fuel oil and the increased availability of high quality NSW coal at good prices.