Before the stock could be moved from the BSC depot to Wansford allowing access to the Nene Valley line .
Wansford is the missing 400 yards ( 366 m ) of the Fletton Loop had to be rebuilt .
Before the stock could be moved from the BSC depot to Wansford , the missing 400 yards ( 366 m ) of the Fletton Loop had to be rebuilt , allowing access to the Nene Valley line .