REGISTER

Peter Burns

MBA, BAppSci(Elect), CPEng, FIRSE, FIEAust

Director, PYB Consulting Pty Ltd

Today’s railway fatalities are arguably more likely to occur at level crossings than in the train collisions we tend to focus most attention on controlling. Designing for level crossing safety can be messy and grey, especially when the dependence on the behaviour of people, members of the general public, is taken into account.

AS 7658 provides guidance on the minimum warning time applicable for a crossing. It also provides guidance on the maximum warning time applicable unless no practicable means exists to reduce it.

In my experience, the guidance on maximum warning time appears less well understood by designers than that concerning minimum warning times. Some would like to ignore it.

This paper will briefly review the behaviours model which forms the basis for the minimum warning time requirement. It will then look at how excessive warning times (based on AS 7658 threshold) can lead to unsafe outcomes.

Two illustrative level crossing cases will be presented (one for pedestrians and one for road vehicles) demonstrating the reality of reduced safety from excessive operation.

The importance of context and the crossing user’s expectations in determining safe outcomes is discussed. An illustrative example from the world of cricket will be provided.

An historic case will be looked at where a number of fatalities occurred at a particular crossing at a rate of around 1 every 3 years up till when it was finally grade separated. An additional incident happened at an adjacent crossing. Both crossings have since been grade separated, but there are too many level crossings to grade separate all of them within the lifetime of even the youngest of our members.

Design associated with level crossings (to allow for all operations and behaviours at each location) can be quite complex when the need to avoid excessive ring times is included as a requirement; but worthwhile. Safety requires warning times to be optimised, not maximised.