[
    {
        "role": "user",
        "content": "WHAT%20IS%20A%20CASDO%20ON%20TPE%20TRAINS"
    },
    {
        "role": "assistant",
        "content": "On TransPennine Express (TPE) trains in the UK, **CASDO** means \u201cCoach-based Automatic Selective Door Operation.\u201d ([railforums.co.uk](https://www.railforums.co.uk/threads/tpe-sheffield-short-platform.282374/?utm_source=openai))\n\nHere\u2019s how CASDO works and why it matters:\n\n---\n\n### What is CASDO?\n\n- CASDO is a system used in certain train carriages (coaches), especially the Class 185 sets operated by TPE. It detects which parts of a train are safely aligned with a platform and only allows the doors in those coaches to open. ([railforums.co.uk](https://www.railforums.co.uk/threads/tpe-sheffield-short-platform.282374/?utm_source=openai))  \n- It uses beacons (also called balises) located at either end of the platform. When the train passes these beacons, the onboard system knows which coach\u2019s doors are \u201csafe\u201d to open. ([railforums.co.uk](https://www.railforums.co.uk/threads/tpe-sheffield-short-platform.282374/?utm_source=openai))\n\n---\n\n### Why does CASDO exist?\n\n- Platforms at some stations are too short to accommodate the full length of all coach doors. If a train is longer than the usable platform, opening all its doors would be unsafe (leaving large gaps, or doors opening off-platform) ([railforums.co.uk](https://www.railforums.co.uk/threads/tpe-sheffield-short-platform.282374/?utm_source=openai)).  \n- CASDO ensures passenger safety by only allowing doors that are next to the platform edge to open, and keeping doors that extend beyond the platform closed. ([railforums.co.uk](https://www.railforums.co.uk/threads/tpe-sheffield-short-platform.282374/?utm_source=openai))\n\n---\n\n### How it\u2019s used in practice\n\n- For instance, if you're on a 6-car Class 185 train arriving at a station where only 5 cars can be accommodated, CASDO will disable the doors on the coach that\u2019s not aligned with the platform. Passengers are usually notified that only certain portions of the train will have doors opening. ([railforums.co.uk](https://www.railforums.co.uk/threads/tpe-sheffield-short-platform.282374/?utm_source=openai))  \n- The guard or conductor may have the ability to override or adjust door-opening behavior depending on station layout. ([railforums.co.uk](https://www.railforums.co.uk/threads/tpe-sheffield-short-platform.282374/?utm_source=openai))\n\n---\n\nIf you want, I could give examples of which stations along your route use CASDO\u2014or how to tell by seating whether you should be in a specific coach."
    }
]