Re: Train WiFi was actually that bad for a while
They state that they block streaming and potentially other large / voluminous data transfers (photo sync would be obvious). I've never used it for much and generally go via 3G/4G as it's generally better on a busy service but will have a gander next time I'm on the train.
Like many wifi sites your persistent TLS stuff like Outlook will throw cert errors when you're at the captive portal page because of how DNS works for captive portals but once through the portal it's all rosy.