Hello, do any trains run on Saturday?
Yes, we have many trains that operate on Saturday. Would you like to book one?
I'm looking for the train which arrives in Cambridge from Leicester. It should arrive by 19:30
Is there a time you would like to leave by?
No I don't have a leave time preference. Just not too early if I don't have too.
How about 9:09 will that work for you?
That might be too early. 
What is the earliest you would be like to leave by?
I'll take the one that leaves at 9:09.  It's fine.  What is the travel time on that train?
The travel time on train TR8070 is 105 minutes.  Would you like me to book this for you?