I could go there now and the ones that you did would be wrong, different companies have different ways of measuring them, though they should all be done the same way.
Some use tape some use laser gauges and some believe it or not measure it from the wrong edge of the rail
If i see this question again i will flip!
Please can we have a sticky saying this is a secret railway thing that railway chaps know about but is of no concern to you. Move along. Nothing to see here, move along!