Keeping a plain miles-long tube at at least 90% vacuum seems pretty hard to me, especially when needing to deal with evacuations and possible breakages. Why not

Keeping a plain miles-long tube at at least 90% vacuum seems pretty hard to me, especially when needing to deal with evacuations and possible breakages. Why not divide the tubes into discrete sections gated by movable airtight caps that side away while passing through? If one section repressurizes due to evacuation or some other fault, so be it.