I've been collecting the Nm(ish) Kato RhB range and decided I needed a test piece to run them in on and testsome ideas for the layout. I had a chunk of foam left from another project so that dictated the size of roughly 2.5 x 1.5ft.   So I marked it out and cut the tunnel section into blocks my hotwire could get through so I could carve the tunnel as a lower level. The tunnel is a 8 piece 3D jigsaw   I started attacking it with the hotwire to get the basic shapes and two bridge blanks.