Building an Inverted Train Tunnel

Part of the process of building up the new layout has involved creating a few train tunnels of varying heights and widths. Up until recently I’d gone for either very narrow tunnels using the 1×12 arch pieces, or wider, more boxy looking versions using half arch pieces. Neither of these ever looked fantastic, they did the job but it all looked a bit flimsy and unconvincing. I did build a more detailed tunnel entrance once, using some old flex hoses threaded through technic bricks to create a wider portal. I’d like to revisit that idea one day.

This new tunnel needed a bit of an odd shaped footprint as one side would need to connect to the waterfall module. The first steps were to rough out a basic template to build on using big plates and bricks. They aren’t pictured here, but the longest bricks available are 2×24 and I’d highly recommend picking up a few as they’re incredibly useful for measuring studs across distances.

Once the basic template was sorted, I started to build up one side of the inner walls. Because Lego doesn’t offer a great range of inverted slopes, my idea was to use normal slopes but build the whole arch upside down and connect it using SNOT bricks.┬áIt actually worked better than I’d expected, although there was a lot of trial and error in getting everything to stay in position securely. The same technique works well for double track tunnels, and the aforementioned 2×24 bricks are super useful for adding strength in wider versions.