High-speed sleeper D941 from Shanghai to Shenzhen. There are rooms with four and two beds, but booking them, at least through cTrip, feels a bit chaotic. The beds are very slim and hard, but generally comfortable. The couch seems to be primarily used by staff. You get basic toiletries and water for the 10h, 1623km ride. There are two toilets and a water boiler in every car, but no showers.