Rail Condition Monitoring Extends Service Life of Electronic Multiple Unites

PCMS Engineering worked with a train operator to extend the in-service life of their 16 car fleet, 30-year-old Electric Multiple Units (EMU’s) by utilising a range of rail condition monitoring solutions.

The Challenge

One of the key elements was to undertake a fleet-wide condition assessment of the onboard pneumatic systems and make appropriate recommendations for ensuring future reliability.

The Solution

The assessment was undertaken by PCMS and used a wide range of condition monitoring tools and technologies including ultrasonic, vibration analysis, stress wave testing, thermal profiling and oil sampling.

Based on their previous experience with condition assessment and rail condition monitoring programmes, PCMS engineers were able to select the optimum data collection points and combine the results of the different tests to select the most relevant data on which to undertake the subsequent analysis.

At the end of this assessment and analysis, a comprehensive report was submitted indicating the actions required to bring each car in the fleet up to a satisfactory level of operational performance which could also be used as a base-line to monitor the on-going condition.

The Results

62% of the fleet’s compressors were found to be operating outside the operator’s specified acceptable parameter of 20 cycles per hour. Undertaking a pressure drop test on the valve blocks on all vehicles revealed a reasonable correlation between the volume of leaks and high compressor cycle times, however, the main conclusion was that it was the severity of leaks that correlated strongly to units with the highest compressor times.

Key Findings

  • Thermal analysis indicated that compressor cycle times had no adverse impact on compressor temperature and that compressor cooling was satisfactory on all units.
  • Vibration analysis revealed that 5 units had excessive vibration levels and required an examination and possible replacement of the mountings. The motor bearing on one unit required re-lubrication.
  • Testing of pipe thickness using ultrasound revealed a wide variation of deterioration in pipe thicknesses between the three carriages in a 3 car unit.
  • Laboratory analysis of oil samples from the compressors was satisfactory in all but 3 cases, for which an oil change and analysis of further samples were recommended.

Based on the analysis undertaken, and subject to the satisfactory implementation of the actions recommended, there appeared to be no reason that the pneumatic systems on this fleet would not be capable of supporting a life extension as desired by the train’s operator.