Thanks.
Problem is, because it's a re-skin, I'm limited by quirks with the original model. Every section where there is wide spot for a poster is the same, with some flipped. For the rest of the interior sides, one texture is flipped and used for both sides. I can't tell from the interior photos if they have a full size route map like most metro cars, so I think I will stick with the metro route map as my one interior poster. The MARTA model just left the walls completely white. The texture map looks like it was designed that both walls could be mapped or else one wall and the ceiling, but then they used the same section for each poster wall. Are the route displays centered over the middle windows? I can't tell from these angles. The barriers by the doors are actually part of the texture used for the exterior. I don't think there is any way to make them transparent, and it would be a pain even if it were possible. Also, the barriers in the model are the wrong shape and position.
Also does anyone know if the roof of the 7000 series is ribbed or smooth?