Understanding headways: Signet Weekend 2003 Handout

[Peter]

But if train 1 has only just cleared the overlap, train 2 has already passed a YY aspect in the signal prior to it's position in the diagram so could not have been running on greens?

Lesson number 1 for self - look at the diagram before answering. I see what you mean given the number of signals shown. Not quite sure what PJW was meaning.