Unless it's a one way road, you should drive no faster than the speed which would allow you to stop in half the distance you can see.
This is just getting stupid now. Where is this quote from? I can think of many "blind" bends on A and B roads where you'd have to slow to 15mph and likely have a car (or worse) thwack you up the rear!
Besides, trains are totally different to cars as they are on a clearway which is assumed to be totally clear for the section ahead and speed limits set accordingly. Comparing the two is like comparing an F1 car and a milk float (unless you drive for ATW lol)