Cranes lift components of Tunnel Boring Machine (TBM) in Moscow, capital of Russia, June 3, 2018. Since August 2017, China Railway Construction Corporation Limited (CRCC) has been building a 4.6-km section and three stations on the "Large Circle Line" in Moscow, which will be completed by the end of 2020. In February this year, CRCC won another metro construction contract and is expected to start tunneling in December 2019. (Xinhua/Bai Xueqi)

A worker is seen at the construction site of a subway station in Moscow, capital of Russia, April 5, 2019. Since August 2017, China Railway Construction Corporation Limited (CRCC) has been building a 4.6-km section and three stations on the "Large Circle Line" in Moscow, which will be completed by the end of 2020. In February this year, CRCC won another metro construction contract and is expected to start tunneling in December 2019. (Xinhua/Evgeny Sinitsyn)

People prepare a crane at a construction site in Moscow, capital of Russia, June 3, 2018. Since August 2017, China Railway Construction Corporation Limited (CRCC) has been building a 4.6-km section and three stations on the "Large Circle Line" in Moscow, which will be completed by the end of 2020. In February this year, CRCC won another metro construction contract and is expected to start tunneling in December 2019. (Xinhua/Bai Xueqi)

People work inside a Tunnel Boring Machine (TBM) in Moscow, capital of Russia, Jan. 25, 2019. Since August 2017, China Railway Construction Corporation Limited (CRCC) has been building a 4.6-km section and three stations on the "Large Circle Line" in Moscow, which will be completed by the end of 2020. In February this year, CRCC won another metro construction contract and is expected to start tunneling in December 2019. (Xinhua/Bai Xueqi)

Photo taken on April 5, 2019 shows the Tunnel Boring Machine (TBM) at a construction site in Moscow, capital of Russia. Since August 2017, China Railway Construction Corporation Limited (CRCC) has been building a 4.6-km section and three stations on the "Large Circle Line" in Moscow, which will be completed by the end of 2020. In February this year, CRCC won another metro construction contract and is expected to start tunneling in December 2019. (Xinhua/Evgeny Sinitsyn)