How Does A Mega Tunnel Under The Alps Get Built? | Richard Hammond’s Big

Richard Hammond shows how the Brenner Base Tunnel is built using massive machines and ingenious engineering techniques that will make it the worlds seconds longest railway tunnel when opened. 🇬🇧 Catch full episodes of your favourite Quest shows on discovery+: https://bit.ly/2Nz890S Subscribe to Quest TV for more great clips: http://www.youtube.com/subscription_c... Follow Quest on Twitter: https://twitter.com/QuestTV