Seasonal Currancy

What do we do with all of the seasonal currency that we are getting from the premium pass?
I’ve collected everything on offer, 10 train cards all of the expansion and storage items plus the station etc. and I’m still going to collect another 2000+ seasonal currancy before the end of the mayors challenge! I’m currently on tier 24.

Am hoping that we will be able to get more train cards etc as we need 40 to get the train itself otherwise all of the coins we collect will not be used.