Eu projetaria assim:
Journeys:
- ID
- Other info (billing, whatever)
Segments:
- ID
- JourneyID (FK)
- departure, arrival, etc
E uma visão adicional
Journeys_View
- Journeys.*
- First departure
- Last arrival
Journeys:
- ID
- Other info (billing, whatever)
Segments:
- ID
- JourneyID (FK)
- departure, arrival, etc
Journeys_View
- Journeys.*
- First departure
- Last arrival