In a next update it would be great if it would be possible to convert track parts in to terrain. Than aligning or joining multiple track parts perfectly is no problem anymore. Also you it make runoff areas with aligned textures possible. Just convert the trackpart into a terrainpart (while keeping the texture direction) and than glue it to the rest of the terrain (and delete the vertexes you don't need anymore). You can still keep a inactive copy of the part you converted for later use or if you need to redo something.