Self-Education ~ Hot Summer = Slow Speeds
"High temperatures in many parts of Victoria provide a timely reminder that V/Line services can be affected when the mercury climbs into the 30s.
As a safety precaution track operator Pacific National imposes speed restrictions on V/Line trains when the forecast temperature is 36 degrees and above (32 degrees and above for some sections of track in outer regional areas).
This has been standard operating procedure in the Victorian rail industry for more than 10 years.
High temperatures can affect rail track and the speed restrictions are designed to ensure trains are able to continue to operate safely.
Pacific National has advised that when speed restrictions are imposed during the summer, V/Line trains will not be able to operate above 90 km/h."
Hooray, this fills me with joyful anticipation and not only do we have to worry about carriages that have defective air-con (even the new V'locity's suffer this issue, especially when left standing in the sunlight in the yards all afternoon), but commuters will enjoy the extra 10~15 minutes added travel time.
Anyway, this led me to read up on railway tracks and I learnt about "sun kink" which is an issue that can cause derailments.
"Engineers try to heat the rail to a temperature roughly midway between the average extremes of hot and cold (this is known as the 'rail neutral temperature'). If temperatures reach outside normal ranges however, welded rail can buckle in a hotter than usual summer or can actually break in a colder than anticipated winter."
So I'm thinking that as soon as temperatures get above 32~36 this is the 'rail neutral temperature' that our new tracks between Geelong & Werribee (were the new tracks were laid), are rated for. You learn something new every-day.
It still doesn't make me happy, but you can't argue with science & engineering and safety precautions!