The cab whistle's shrill "pheeeeep-pheeeeeep" sounds in the FPA4 cab as the conductor pulls twice on the trainline. The engineer reaches for the controls and he replies with two toots on the air horn. The train is about to leave the station.
The finality of departure, coupled with the anticipation of the journey are wrapped up in the sounds of air whistle, air horn, and engines throttling up.
Same goes for my book. Everything is in readiness. The text, data and photos have been selected, gathered and are ready for the next step in the journey. Supporting rosters, schedules, some historical notes and data. Lots of data. This step will involve transmission from computer files to paper. Finally. Highball!