Dyan Crowther took part in Operation Raleigh in Chile and then undertook various roles before joining British Rail as a Graduate Entrant Management Trainee in 1986. She then served as the Station Manager at London Bridge, Peckham Rye and subsequently at West Croydon. After privatisation she was appointed as the Managing Director of Arriva Northern in 2002, she served in this capacity until 2006 when she joined Network Rail as Zone Director for the East Coast Main Line until 2010. She was appointed as Operations Director at Network Rail in 2010, staying in this role until 2015. She worked as Route Director for the West Coast Main Line at Network Rail from 2012 to 2015 when she left Network Rail and joined Thameslink as Chief Operating Officer, Thameslink until 2018. Since 2018 she has been the Chief Executive Officer of HS1 Ltd.