Where are you departing from? Do you have a day you would like to travel?
I'd like a train to Cambridge that arrives by 19:30. I'm departing from Ely. Yes, Wednesday. I also need the departure time and price, please.
{"__type": "Request", "service": "train", "values": ["day"]}
{"__type": "Inform", "entity": {"__type": "Train", "arrive by": "17:52", "day": "Wednesday", "leave at": "17:35", "price": "4.40 pounds"}}
The latest train arrives at 17:52 on a Wednesday, departs at 17:35 and the cost of the ticket is 4.40 pounds.