In November 2001 National Express signed a contract with Bombardier Transportation for 29 two-carriage diesel multiple units. This was later extended to 38. The design was an evolution of the Xplorer/Endeavour railcars.
After the initial order of 38 units, a further two VLocity units were later ordered to bring the total to 40, along with 22 new intermediate trailers to be inserted in the middle of existing VLocity sets. The first 14 were promised during the 2006 State Election and the order was placed in December the same year and the order for the next eight was announced on 12 October 2007.
In July 2008, the State Government unveiled a $236 million package of regional rail improvements, including nine new three-car units, and an additional intermediate car to be inserted into an existing two-car unit.,with an extra four carriages added in February 2009. The final unit of the order was delivered in September 2011.
In November 2012, the State Government announced an additional 40 carriages will be delivered between 2014 and 2016. The order will comprise seven additional 3-car sets plus 19 intermediate cars.
In March 2014, the State Government announced that the existing order for 40 carriages would be increased to 43