Aren't braking distances so large because of the massive amounts of mass in motion? Inertia, etc. Even high certainty of track friction wouldn't change that.
Also, I don't think it's ever safe to be closer than braking distance because the bahavior of the train ahead is never guaranteed. There's always a chance somebody parks their car on a rail crossing or some other sudden stopping-event occurs.
No, they’re very long because steel wheel on steel rail has much much much lower coefficient of friction than rubber on asphalt. If they brakes any harder they wheels would just lock up and skid, both running the wheels AND taking longer to stop than a normal braking application.
The costs involved with libel cases are nothing short of eye-watering [1]. Strict libel laws are pointless if you can't afford to bring a case. (Though, there are "no-win, no-fee" agreements available)
Defaming a third party by telephone would more likely be slander than libel, but it's certainly not clear that what went on here would be defamation at all.
A defamatory statement must be a false factual allegation. As long as what the headmaster claimed was true, he should be safe from libel or slander lawsuits - saying "I don't like this guy's politics and you shouldn't take him on as a student." is a fair expression of opinion, however silly that opinion is, and despite the rather insidious attempt to harm someone's career over a personal/political disagreement.
Mind you, I'd guess that in these sorts of circumstances, Glasgow University would likely thank the headmaster for his concern and file the note of this communication in the waste paper basket, where it belongs. Universities are no stranger to having to fend off third parties - parents, police, stalkers and whathaveyou - attempting to meddle in the affairs of their students; if their admin staff are halfways competent, they already have 50 tactful ways of telling outside interferers to fuck off.
>...saying "I don't like this guy's politics and you shouldn't take him on as a student." is a fair expression of opinion...
Mr. Szemalikowski appears to be claiming that he considered the student, Kinnan Zaloom, to be a potential terrorist:
>He said he had 'major concerns and was duty bound under legal acts for the prevention of violent extremism' and that he was 'erring on the side of caution' in taking action.
English libel law is substantially more friendly to the plaintiff than to the defendant.
I referenced US libel law as a counterpoint to the rest of the world because I thought you were not thinking of the US. There have been several high profile cases of journalists and scientists saying true but defamatory things in the UK about quacks and charlatans and being hounded in the courts. In response to this, the UK has actually passed legislation attempting to remedy the situation, but this has not yet taken effect.
Also, I don't think it's ever safe to be closer than braking distance because the bahavior of the train ahead is never guaranteed. There's always a chance somebody parks their car on a rail crossing or some other sudden stopping-event occurs.