Design and Prototyping of a Robust Linear Variable Differential Transducer Bogie Mounting Bracket for Circle Line Trains

The third rail linear variable differential transducer (LVDT) system is a realtime condition monitoring system for evaluating third rail height on the North-South and East-West Lines and Circle Line in Singapore. However, recurrent fatigue failures in the bolts of the LVDT bogie mounting bracket (BMB) pose a threat to the availability and reliability of the LVDT system as well as impair the visibility of third rail health. This paper, therefore, investigates the root cause behind the reoccurring failures and aims to design and prototype a new, robust LVDT BMB through iterative finite element analysis design methodologies. Analytical results show that under the maximum operational stress of 1400 N, the maximum principal stress experienced by the proposed LVDT BMB was 164.36 MPa, well below its endurance limit of 240 MPa. This can eliminate fatigue failure, thereby increasing LVDT condition monitoring reliability, increasing train availability, reducing corrective maintenance costs, and culminating in total cost saving of about S$29,333.33 annually.