@majuen I tried your solution of setting texture to square dimensions and it worked( i guessed). I only change the dimension size of the dds file(bussteig_1-10) under res\textures\models to 256x256 pixels and dds file(groundblock) under res\textures\streets to 128x256 pixels. Then i saved them using the settings in the picture 1 below after trail and error. My editing software is paint.net.
The result is this picture 2 below.
One thing i noticed while playing around with this stuff is that there is a picture of the mock up bus station with number on it (res\textures\models\busbahnhof_plan). But when compared to the game picture above, the numbering location did not match. Maybe @majuen you can tell me if it matter or not. I attached the pic 3 below.