I do not think so, if they do not ban cache who will pick it? Maybe FaZe, but who else? Cache is a map lots of team 2nd ban cuz none are masters on it. But train, we already saw some weaknesses on train (remember that close 16-14 win over FaZe at ECS, it was FaZe’s fifth map with Cromen and first on train). Also there are a few teams who would pick train: NaVi, fnatic, BIG.
But for their match against C9: it would be still a safer pick. Cache is a map where skill is necessary. C9 have Styko, golden and never been good on cache. While on train, if golden has magically prepared a system on it, they would come close. Also train was a good map for C9 in the fall of 2017.