New rolling stock for the Rinkai Line, the 71-000 series. Stainless steel bodies like everything else these days, but at least they're not stingy with the wrap and it's a nice blue color. These videos are on their official channel. In the first one, the opening scenery (Niigata or thereabouts) and the videography are very nice.
This one is a short front view video of a nighttime test run from Tokyo Teleport to Shin-Kiba. It begins in a tunnel but exits at about 2:50, just before Shinonome Station.
Line map from Wikipedia:
https://en.wikipedia.org/wiki/Rinkai_Line
https://en.wikipedia.org/wiki/TWR_71-000_series