We don't have synonyms for brake van yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are brake-van, brakeman and brake pad.
(n) :
(British, rail transport, dated) A railway vehicle used to brake a (goods) train, usually placed at the end of the train. These were essential before continuous train braking became universal.
(n) :
(British, rail transport, dated) A railway vehicle used to brake a (goods) train, usually placed at the end of the train. These were essential before continuous train braking became universal.