Derailment Risk Assessment of a Freight Wagon due to Cyclic Top

07/10/2024

Infrastructure managers of railway networks inspect and maintain the track to ensure safe operations by following regulations. The track quality is assessed as described in the standards, that is, post-processing track irregularities that are measured from the track inspections. However, some derailments of freight wagons have occurred during the years in tracks where track quality was within the limits. In the report of these derailments, cyclic top is identified as the cause of the derailment, however, this is a track irregularity that is not defined in the standards. Thus, the main goal of this work is to develop a robust method to identify cyclic top. A vehicle model of a freight train that was previously involved in a derailment in Portugal, along with a railway track segment suspected of having cyclic top, are used as case studies. Multibody simulations (MBS) are employed to assess the vehicle-track interaction at several operating conditions, from which high derailment risk cases are identified based on the unloading derailment indicator. Further MBS are performed to determine the pitch and bounce natural frequencies of the wagon. It is shown that a high risk of derailment can show a correlation with the frequency of the vertical track irregularities. This enabled the design of an algorithm that identifies cyclic top patterns based on the bogie spacing of the vehicle wagon, making it possible to be used by infrastructure managers with no knowledge about the vehicle characteristics.

Authors in the community:

• 

  C

  Carolina Cansado Abecasis Corrêa

  ist193228

Supervisors of this institution:

• 

  H

  Hugo Miguel Pacheco Magalhães

  ist163344

• 

  V

  Virginia Isabel Monteiro Nabais Infante

  ist413958

mechanical-engineering - Mechanical engineering

por - Portuguese

Instituto Superior Técnico