The track bed configurations of the TIAA MRT rail at the connecting sections of the maintenance depot are different. The section from the main line entering the maintenance depot is non-ballast track and the track inside the depot is ballast track which results in significant track stiffness difference between the two tracks. Generally at the track convergence of the two different tracks will be implemented with a special method depending on the differences and requirements of the track stiffness. Setting the “auxiliary rail” to increase the track stiffness of the ballast end and to cushion and buffer the stiffness at both ends is one of the commonly used methods. Not only avoiding over-subsidence of the ballast track, this method can reduce the maintenance cost of track bed in this area as well.
The auxiliary rail of the TIAA MRT System is designed as adding two UIC60 rails in between operating rails for approximately 23 meters (18 meters in the ballast track section and 5 in non-ballast track section) and adopted Pandrol fastenings to fix the rails. In addition, in order to increase lateral stability of the sleeper, the sleeper anchoring plate was also installed to strengthen its track bed structure stability.