With a maximum overburden of 240m, the TBM-bored tunnel has passed through difficult geology, including a band of salt 100m deep and frequent inflows of water. To ensure construction continued through the Coronavirus emergency, contractors and engineers implemented measures to ensure the safety of the workforce.

Construction of the 414km-long railway began in 2016 and is expected to be completed by December 2021. With a total 198km of tunnels and 62km of bridges, the railway will form a lifeline to landlocked Laos – one of the world’s last remaining communist states.