Network Rail is to carry out drainage improvement work to cut delays between Crewe and Chester.
The tracks on either side of the Christleton Tunnel, near Chester, regularly flood during wet weather.
Network Rail will be upgrading drainage in the area between Monday and Saturday next week.
The line will be closed to all trains between Crewe and Chester, affecting Arriva Trains Wales and Virgin Trains services.
Network Rail area director Ian Joslin said: “The work in the Christleton Tunnel area will significantly improve performance on this section of line, resulting in fewer delays and a more reliable railway for passengers in the future.”