Discover new possibilities with this custom wood pillar elements which enable tunnels that actually go underneath your track. This project includes three designs for (1) straight tunnel, (2) tunnel curve or branching, (3) looping. You can even stack them to realize vertical falls. 
Tip: You may adjust the height of the elements. One level is about 10mm. 

The project files are for 3mm wood. You may need to slightly adjust it for different wood thickness, such that your pillars fit perfectly in height with original Gravitrax(TM) elements.