There is quite a slipstream around the body of a high speed train; and, railroad rights of way tend to save construction and maintenance money by being only minimally wider & taller than the train body itself requires. True, clearances could be widened at the EVTOL launch and recovery points.Or you'd have your high speed train lauching and recovering individual E-VTOLs along the way,
From Aero Digest 1942,
I think it was just idea ?.