I often ride the 2 miles to the railway station.
A "station bike" is a bit like a pub bike, you need something fairly low cost, simple, and low-key.
You need reliability and convenience over speed.
I would opt for a 3-speed with dynamo lights, maybe a shopper style or an old gents 3-speed. Pashley make new, fancy ones, but car-boot sale versions are just as good over 3 miles. Single-speeds and 1x8 transmissions also works well.
Folders are a bit more expensive and really meant to carry with you. For bus and rail carry (peak time) you need one of the more compact (and expensive) models.
Dynamo lights are surprisingly unattractive to vandals and you don't have the bother of carrying extra stuff.
Tyres are the one component where you need quality, and this calls for Schwalbe Marathon Plus. No repair kit needed.