The funniest argument and the reason I share this is that since the utilities company that provides the tram service has a ratified goal of becoming CO2-Neutral eventually, they’ve elected to not buy ACs since they’d consume about 7 million kilowatt hours of electricity per year and ACs aren’t sustainable. I assume the 50°C tram is gonna be a big hit as per transportation in the upcoming summers.
I assume this was part of it, all the train infrastructure is barely holding it together in like 15°c weather at this point but the stated, publicized reason was as above. So probably less “we’d derail our entire shit” and more “You’d be stuck in a train where the AC broke in the middle of nowhere” and then that just gets resolved to “be stuck with no AC somewhere you need to leave and collapse there”