Nov 13, 2015 - If you read my Up the Creek column in Model Railroad Hobbyist, you may remember my writing about tunnel liners in the May/Apr 2010 issue of MRH. I still had the foam tunnel core I carved to make tunnel 3. Using it to make the the Siskiyou branch tunnel liner was a no brainer. This time, instead of wrapping it was crumpled up aluminum foil covered with plaster to similate blased rock, I layered it with plaster cloth.