The name on the equipment shown in the video indicates that the constructor of the railway here is a subsidiary company of the state-owned China Railway Group, one of the Top 500 companies in the world.
China currently has 23,000 miles of high-speed railway in operation, out of the total rail mileage of over 90,000 in the country.High-speed trains are those that run at speeds ranging from 155 to 220 miles per hour. In 2020, in spite of the Covid-19 pandemic, trains, fast and slow, transported over two billion passengers across China.
High-speed trains has made traveling in China much easier. It used to be the case that a train ride between Beijing and Shanghai took over 24 hours. Now it takes just 5 hours to cover the 800 miles between the two cities. Theoretically, someone could take a train to go from Shanghai to Beijing in the morning, get his business done in the afternoon, and return to his home in Shanghai that very night.
In the clip shown here, at one point smoke comes out of a small dwelling below the viaduct being built. It must be a local peasant family cooking its meal. What's old and what's new are so close to each other, that's China today.