Not just repairs, but track and tunnel conditioning monitoring, checking the tension in catenary lines, the maintenance of the trains themselves, etc. Is every

Not just repairs, but track and tunnel conditioning monitoring, checking the tension in catenary lines, the maintenance of the trains themselves, etc. Is every track maintained every night? No. But: * it is incredibly dangerous for a high speed train to collide with anything low speed (track maintenance vehicles, supplies, or workers). The rights of way are so constrained that there is no safe way to have them maintain only one track out of two, so they insist on total separation as a policy: https://international-railway-safety-council.com/wp-content/uploads/2017/09/sasaki-safety-system-for-track-maintenance-vehicle-operation-of-shinkansen.pdf https://international-railway-safety-council.com/wp-content/... * the Shinkansen are a two track network without parallel lines of the same gauge, so any maintenance reroute would require changing to either a normal train or to a bus, making sleepers impossible to operate normally. Even if you could though, trains need regular schedules for both riders and employees, and using different reroutes every night would be a scheduling nightmare