We don't have synonyms for running days yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are running day and running dry.
(n) :
A day on which vehicles, locomotives, etc., are run or driven, especially when these are otherwise kept or exhibited statically, such as at a museum.
(n) :
Any of the days occupied on a voyage, etc., under a charter, including Sundays.
(n) :
A day on which vehicles, locomotives, etc., are run or driven, especially when these are otherwise kept or exhibited statically, such as at a museum.
(n) :
Any of the days occupied on a voyage, etc., under a charter, including Sundays.