Mumbai-Ahmedabad bullet train corridor gets high-speed movable crossings

A movable crossing eliminates the gap by shifting the crossing nose in coordination with the switch rails. This creates a continuous running surface and maintains uninterrupted wheel guidance through the turnout.

The Mumbai-Ahmedabad High-Speed Rail (MAHSR) project is introducing turnouts equipped with movable crossings, also known as swing-nose crossings, for the first time on the Indian railway network, a technology designed to support safe and reliable train operations at speeds of up to 320 kmph. According to an official statement, the movable-crossing technology is being adopted as a key component of the high-speed railway system and marks a departure from the fixed-crossing turnouts used on conventional railway lines.

At speeds exceeding 250-300 kmph, wheel-rail interaction at a conventional fixed crossing can generate higher dynamic forces because of the gap at the crossing nose, according to the project details. Such discontinuity can result in increased vibration and structure-borne noise, accelerated wear of wheel flanges and crossing components, and irregular wheel behaviour under residual track irregularities.

A movable crossing eliminates the gap by shifting the crossing nose in coordination with the switch rails. This creates a continuous running surface and maintains uninterrupted wheel guidance through the turnout. The technology is expected to facilitate smoother passage through turnouts, reduce dynamic impact, vibration and interior noise, and lower wear on rails and rolling stock.

The high-speed turnouts are also equipped with two independent point machines. The switch-end point machine operates and locks the switch rails, while the movable-crossing point machine operates and locks the movable crossing nose. Both point machines operate under a coordinated control system. A signalling interlocking route-setting command initiates the movement of the switch rails and movable crossing, with position detection and locking confirmation required from both machines before a train movement is authorised over the turnout.

The dual point-machine arrangement ensures that the continuous rail path is established and mechanically secured at both critical locations. High-speed point machines are required to meet stringent technical requirements, including precise stroke control, tight positioning tolerances and robust locking mechanisms capable of withstanding the forces generated during high-speed operations.

The system also incorporates multiple detection and verification layers to monitor the final position and mechanical locking of the switch rails and movable crossing. The interlocking releases the route only after the independent checks confirm that the turnout has been correctly positioned and locked.

The adoption of movable-crossing turnouts with dual point-machine operation is aimed at supporting the MAHSR corridor's requirements for safety, ride quality, asset life and operational reliability at speeds of up to 320 kmph. (ANI)