PIM

The Train Accident Precursor Indicator Model (the PIM) managed by the Rail Safety and Standards Board (RSSB), measures the risk, per million train miles, of a train accident - i.e. collision, derailment, fire or striking a road vehicle on a level crossing. The measure incorporates 82 precursor events in eight groups. Around 65% of the risk arises from events largely under the control or the responsibility of Network Rail, e.g. track geometry, infrastructure failures, environmental factors (flooding, land slips etc.) and level crossing misuse.

The PIM risk indicator was set to a reference value of 100 at the end of March 2002 and the PIM risk indicator provides a measure of the change in risk relative to this level. A reduction in the index is therefore beneficial, denoting a reduction in risk.