Tudor Hughes wrote:

It doesn't make any difference which way the railway is
aligned; the right-hand rail is always more affected but the amount is
negligible. The force for a train travelling at the routine 125 mph is
0.0006 times the weight. This is the same as travelling at that speed
round a left-hand curve of about 140 miles radius. Not exactly a
hairpin bend, even for a railway. The effect of a moderate side wind
would be at least an order of magnitude greater, as would a few extra
passengers on the right-hand side of the carriage. There may have been
a difference in the wear in steam days because the right-hand cylinder
always leads the left-hand one.

I should like to know where this somewhat mystical data has come from
and how.

When you next see a film of WW II aircraft taking off, try and get a
look at the set of the rudders on the planes. All the British ones were
angled right IIRC (when the pilot wasn't weaving to try and see where
he was going) because the engines most in use were the Rolls Royce
Kestrels, Merlins and Gryphons. And they all rotated the same way.

The problem was particularly pronounced in the Mosquito apparently. I
vaguely remember the story of a pilot new to them, giving a VIP a tour
of the hangars and stores instead of getting them up and away. :~))