By Tristram Gethin The economic value the Elizabeth Line has brought to London cannot be underestimated, but we can’t stop there. Two years on, it’s time to think about how we can build on its success, says Tristram Gethin Today the Elizabeth line celebrates its second anniversary. Speak to Londoners about the impact it’s had, and you’ll be met with words like ‘gamechanger’, ‘transformational’ and ‘revolutionary’. All are a reference to how Europe’s largest infrastructure project has slashed journey times across the city, opening up places by creating new connections, and boosting London’s eco…