It's hot today in Boston, but not never before seen hot like in the PNW. The previous all time record high before this week in Portland was 107 degrees, yesterday Portland hit 116 degrees. The current heat out there is way past what would could be foreseen when designing rail infastrcture.
Kind of surprised the T's alert tracker is devoid of any heat-related delays. Today is prime heat-kink weather for welded rail on rapid transit and commuter rail.
On the other hand, we usually have temps in the high 90s once or twice a year. Not unheard of.