1) Kaa-ching! You can't just bury it as a gas tube. It has to be suspended in a tunnel to allow for ground movement compensation etc. 2) Kaa-ching! Both upfron

1) Kaa-ching! You can't just bury it as a gas tube. It has to be suspended in a tunnel to allow for ground movement compensation etc. 2) Kaa-ching! Both upfront and ongoing. 3) Kaa-ching! There is reason materials such as Invar are not found in railways, and cost is only one of them. 4) There is no precedent to using vacuum seals at that scale (or maintaining vacuum in that sort of volume). Elon Musk just says "let it be suspended on roller supports so the terminals slide dozens of meters". Nothing wrong with that surely.