Andrew Kish
Kandrew Inc. Consulting Services
Abstract:
Hot Weather Speed Restrictions: Do We Need Them?
Current industry practices on speed reduction at elevated temperatures vary and are based on limited knowledge on buckling temperatures and on contributing parameters such as rail neutral temperature (RNT), ballast strength, and track quality. Hence current speed restriction policies often result in highly conservative blanket heat restrictions with severe impacts on revenue and put-through capacity. To remove/reduce such impacts yet still maintain CWR safety, recent industry efforts have focused on a better understanding of buckling mechanics and its relevance to speed restriction benefits, in particular to: (1) what extent is buckling risk reduced through speed reductions, and (2) when and where to impose if needed?
These questions will be addressed in this presentation. In particular, basic buckling risk aspects will be discussed, and a new approach will be introduced to determine temperatures at which speed restrictions should be applied to reduce the risk of track buckling. The approach is based on current best practice guidelines to evaluate the track’s buckling strength in terms of “safe” allowable temperature increase limits, and on a rail operator accepted “buckling risk index”. Illustrative examples will be provided to demonstrate the method and its application.
AS SUBMITTED:
A new approach is introduced to determine temperatures at which speed restrictions (SRs) should be applied to reduce the risk of track buckling. The approach is based on current best practice guidelines to evaluate the track’s buckling strength in terms of “safe” allowable temperature increase limits, and on a rail operator accepted “buckling risk index”. Illustrative examples demonstrate the method’s application.