2 aspect headway

[Peter]

Hi PJW,

Thanks for the fast response, so that's my first error I shouldn't have referred to this as 2-aspect. The example included is of shunt signals.

I guess in calculating headway in this scenario I need to make some assumptions about the operational practice: for example always start from rest?

Small point, the Peter that is PJW is differnt to the Peter that is Peter.

Certainly if you are talking about trains moving onto a running line and taking up capacity, you will need to think about the time it will take to get out, get ready and move out of the section. Since you would not normally have running moves from shunt signals, assuming trains would be starting from rest is likely to be valid.

It would be helpful if you draw out what the scenario is and ask specific questions as there are too many variables to work out exactly what you are struggling with.

Peter