Great writeup! Planned doing the same thing Herr in germany. Thought a Smartphone camera would be enough but there no way to access the camera2 api for those highspeed recordings. I took 1h long 240hz 4k vertikal videos (out of the Schwebebahn in Wuppertal) which could be displayed by MacOS preview. Right no im waiting for a good gaussian splatting tool to create the driving of the "Train” in Blender. The newest Lingbot-map is unfurtunatly not really trained for sideway movement. I always asked myself if the sideway movement and the Parallaxe would make way easier to infer the distance and the 3d scanning capabilities because the pixel only really move one as long you dont drive turns

Ohhh, nice; happy to have a chat on the subject; suggest a messaging option to discuss further if you're interested. Check out keybase on my profile for some listed contact options; you can also use the padlock symbol in the menubar there to PGP encrypt a message to me and share that through any suitable channel that can handle that ascii.

Edit: I've captured and extracted-to-textured-mesh Mirker Bahnhof before it got covered by the scaffolding; if you're going to do another recording I'd highly recommend you include an IMU recording and ideally (though much less critically) a GNSS raw measurements recording that includes carrier phase. I've got a recorder for the latter that exposes a simple USB-serial port that should work great unless the GTW15 windows are EMI-shielding (but iirc they aren't).