In the world of (a popular train simulator by N3V Games), CDP stands for Content Dispatcher Package . It’s the standard file format for distributing custom assets like locomotives, routes, scenery, and rolling stock.
Trainz compresses textures into a binary .texture file. Solution: Use Images2TGA or PEV's Images2TGA tool (part of the Trainz Asset Creation Toolkit). This converts .texture to editable .tga . After editing, use TGA2Texture to convert back.