Many of us have tried to forget the historic heat of Late June. Sadly, even Link trains had to reduce speeds. Areas south of the DSTT ran as slow as 20mph and caused delays of 3-10 minutes. This surprised me: elsewhere, Light Rail often operates in temperatures well in excess of Late June’s. ST’s John Gallagher explains:
There are basically two things going on. One is that extreme heat can cause the rails to expand and change shape. The other is that the turnbuckles that keep the overheard catenary wires taut can expand, causing the wires to sag a bit. Out of caution, we operate Link at lower speeds when it’s very hot to ensure that neither of these problems interfere with service should they occur.
Mr. Gallagher says that ST has already added air conditioning to substations to make them more resilient. New track extensions include a spring system on the overhead wires to replace the balance weights on the original track, which should improve heat resistance. He adds that ST will conduct a review to see if there are other changes necessary for a warming world.
Without overreacting to a single instance of record heat, all trends suggest that there are more and more extreme heat events coming, and ST should look to mimic systems like Phoenix that already deal with those conditions.