I just contacted MBTA and Keolis with permission about adding their MPI HSP46 with Rotem Bi-levels as a paid DLC for Train Simulator 2021 and the permission was granted. The huge question is, can someone make the MBTA MPI HSP46 with Hyundai Rotem Bi-Levels? I really want this DLC very badly. And I'm not good at making these content. I wish the developers can make these MBTA Bi-levels. I have autism and I love trains and love these Rotem bi-levels.
We need an actual route for them 1st, there is no MBTA route for TS2021, only TSW2 has the Boston route in the works.
You can do it with certain assets, like locomotives and rolling stock, but not actual routes from what I know.