Methinks this thread has degenerated into uk.railway over analysis and
trying to put literal meaning behind words.

EB NB WB SB are merely vague terms in relation to compass directions
but very specific terms of opposing directions of running.

No more emphasis on EB NB SB WB should be taken than on Up and Down -
trains do not literally go Up or go Down.

There is no ore to the LU terms than that.

--
Nick