SIGNAL+DRAHT | Issue 04/2003
Evaluation of Field Data versus Reliability Prediction in Accordance with Military Handbook 217F
This paper describes the basis for and procedure used in a recent analysis of field data from electronic interlockings equipped with Siemens SIMIS C systems. A comparison of the results with preliminary reliability calculations based on the Military Handbook 217F and adapted on the basis of findings at Siemens showed a significant difference between the derived mean times between failures (MTBFs). The preliminary predictions have been exceeded by a factor of about 4 in the field. It was therefore decided for future reliability analyses at Siemens Transportation Systems, Rail Automation (TS RA), to follow SN 29500, which uses more up-to-date information and the models described in IEC 61709.