I bid 4♠ since I don't envision a good ending in a slam. Partner is short in my long/good suit and I'm short in his other suit. Of course I have a maximum in HCP's but 4♠ won't close the bidding in most hands slam is on. Or so I hope. I had not fully understood the last train option here, so I'll change to that, 4♥. It's better than not showing interest at all, I suppose.