Here's a short video preview of the track building tool that I've been testing in an early alpha version of Train Game 3D. The track tool lets you select a starting point at the edges of a tile. Then, with a start point set, you can see a preview of the potential next connection points (or a red line if not allowed) and you left click to place a track segment. Pressing the space bar will unlock the start point which lets you select a new starting point. There are currently 19 unique track parts that can be combine in a variety of ways and rotations to create a lot of variety.