As an aside from pulling the cord but regarding emergency stops - In 1989 I was lucky enough to have a cab ride in an HST from Newcastle - Cardiff(?) as far as Leeds, and on departure from York the driver was routed on the UM not UL (the timetable change was that day and previously the train ran via Doncaster - this day it changed to via Leeds). He sensed something was wrong and upon seeing the feather on the signal at Colton Jn for Doncaster there was a "oh shoot"
[*] brake application from 90 mph which resulted in the cab and 2 carriages passing the green signal. In mentioning this I want to say there was
never any danger to anyone, just the route was set wrong.
As there was a visitor in the cab, [me] there was a traction inspector chappie too, he was the fella who went back to talk to the Bobbie on the SPT. Anyway after a few minutes the train set back and then after the time out was routed via Leeds. The only remark from the traincrew on the emergency application of the brakes was "Crikey
[*] I bet those brakes are stinking back there".
I understand there was later a shunt signal put in place at that junction as it happened too often for it to be an isolated case. No offence meant to any Bobbie in this, just mentioning something I had occasion to witness.
To this day whenever I am on an HST I still can smell those brake pads stinking, an man does it feel good....

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[*] or words to that effect......