So, What I'm starting to summarize here, for example; After the 1S14, the next passenger service via same route would be 1S15 ?
I had a brief look at those links gave by Tosh & M8, a little confusing to start with maybe, but very interesting indeed & useful source of referance,...for example; a loco returning / no passengers (something like that) would have last 2 digits "00" , which seems logical enough really.
Ian, I have noticed in your posts that you seem to use these type of referance's quite often with your huge source of info & notes, thier meanings have never made any sense to myself & many others up to now, so hopefully all who read this thread who were un-sure will understand a little more about headcodes & thier basic meanings.
Without wanting to complicate matters, one other question someone may know the answer to is ;..
- If for example the 1S14 train broke down half way to its destination & needed a tow /replacement loco, would the same detail of headcode digits have be transfered onto the replacement loco or change in some way ? , & on its way to rescue the failed train I assume that the lone replacement loco would need to display "0000" to start with ?
Cheers

,
Dave.