China has started revamping a railway from Baoji in Shanxi province to Sichuan province’s capital Chengdu to enhance the line’s capacity and support rebuilding activities in the earthquake zone.

More than 5,000 workers and 150 oversize vehicles have been deployed on the project, which is expected to take 50 days to complete.

Last year’s earthquake in Sichuan destroyed the southern section of the railway and the No. 109 tunnel in Gansu province. The new tunnel, which will be made of steel-reinforced concrete, will allow trains to reach speeds of 80 kph, up from 60 kph previously.

The Baoji-Chengdu line is as an important transportation route from north China to Sichuan, and it played a significant role in carrying relief goods to places badly affected by the earthquake.