Amidst all the political to-ing and fro-ing, High Speed 2 and its contractors have been getting on with building the UK's first intercity mainline in decades if not a century. Some spectacular engineering innovation has been taking place, delivering savings in carbon, reductions in habitat impact, and improvements in safe working. What are some of the key examples that stick out? How does the rail industry capture this learning and ensure that it can be passed on to other projects and programmes, both large and small? How do we avoid it being lost as political interests rise and fall? Giles Thomas, High Speed 2 Limited's Phase 1 Engineering Director joins Gareth Dennis to explain all.