which it attributed primarily to the fact that passenger numbers had increased dramatically without a corresponding rise in the size of the operator's fleet. The company had suggested to the Department for Transport on at least three occasions that more units should be purchased from Siemens, but had been turned down each time. As an alternative, Porterbrook proposed to enlarge the Class 458 fleet and reconfigure it for suburban services by using vehicles from the fleet, which Porterbrook also owned and which was at that time being released from service with Gatwick Express. The process, budgeted at £42 million, would allow for all 30 original Class 458 units to each be extended by one vehicle, making them into five-car units, after which there would be six five-car Class 460 units left over. These would be comprehensively rebuilt to match the extended Class 458 units, for a total fleet of 36 five-car units that would be designated Class 458/5. The units of this "new" fleet would be used—either individually or in pairs of ten cars—to provide extra peak-time capacity on suburban services into Waterloo from the Hounslow, Weybridge (via Staines), and Windsor lines. A separate improvements package agreed between SWT and Network Rail provided for platform extensions necessary for ten-car operation at over 60 suburban stations, and for the re-opening of one of the four disused platforms at the former Waterloo International terminal. The Department for Transport announced in December 2011 that it had accepted the proposal, and an agreement between Porterbrook and South West Trains was signed in January 2012. South West Trains described the project as advancing their aspiration to become a "10-car railway", and the company's fleet director noted that while the project was "much more complicated ... than buying new trains", it was also "significantly cheaper". The primary contract for delivering the project was awarded to Alstom, who appointed Wabtec to perform the conversion work on their behalf. All 48 intermediate vehicles from the Class 460 fleet were sent to Wabtec's Doncaster Works to be rebuilt and refitted. Eighteen of these vehicles became the intermediate cars in the six "new" Class 458/5 units, while the remaining 30 were prepared for insertion into the existing Class 458/0 units. Twelve of the 16 driving vehicles from the Class 460 fleet were concurrently rebuilt by Wabtec subsidiary Brush Traction at their workshops in Loughborough, where their original driver's cabs were