Possible Clues:

• In-law got disorientated in sleeping car
• During the night continue to be happy, my dog, for the light is on in the train
• Continental sleeping-car
• Comedian performing drunk for the rest of the European travellers
• Awfully long wait for the rest of the travellers on railway
• Sleeper to keep nodding, with light on
• Continental sleeper upset by long wait
• Car that's dropping off passengers
• Dreadfully long wait for the rest of the passengers
• One may be put on for the rest of the continental travellers