We don't have synonyms for guard's van yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are guards van.
(n) :
(UK, Ireland, rail transport, historical) The last carriage on a passenger train which was occupied by the guard, consisted of storage space for parcels, bicycles, etc, and sometimes had an emergency brake.
(n) :
(UK, Ireland, rail transport, historical) The last carriage on a passenger train which was occupied by the guard, consisted of storage space for parcels, bicycles, etc, and sometimes had an emergency brake.