This thread will be dedicated for sightings of X'trapolis and Siemens trains on opposite sides, whether in service or on test runs.
For sightings try and get the lead and rear M carrige numbers, the other numbers can be found on the vicsig site.
State what time you saw it, where it was going/what line it was on. And anything interesting on the desto. Also if there are passengers or crew onboard.
Metro.