Roadbed mud flow always occurs in railway tunnels in waterrich area. The functions of the drainage facilities in railway tunnels specified in standard railway tunnel drawings are analyzed. The drainage facilities in railway tunnels in waterrich area are optimized. The design concept of reducing the water pressure, eliminating the mud flow risks and releasing the seepage water is developed so as to avoid roadbed mud flow in tunnels in waterrich area. Countermeasures, such as adding dewatering wells, adjusting the positions of the side ditches of doubletrack railway tunnels and deepening the side ditches, optimizing the design of the walls of center ditches and adding filter pipe under the roadbed, are proposed. Construction countermeasures, such as horizontal smooth blasting, muck clearing by hand, floor accepting according to standards for concealed works and nondestructive detection are proposed to avoid loose mucks on the tunnel floor. It proves that the countermeasures proposed in the paper are effective and feasible.