Joker loving to snort line, very keen on a party? (4-8)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

An envelope (‘to snort’) of RY (railway ‘line’) in CARD (‘joker’, with the question mark for the indication by example) plus CARING ( ‘living’ ‘ loving ‘ ); the ‘party’ is more political than diverting (at least in the cryptic reading).