Task-oriented dialogue about: train

Hi, I'm looking to take a train on Tuesday and heading to Cambridge.
Where are you leaving from?
I will be leaving from Ely.
ok, what time do you want to depart?
Well I want to arrive by 16:15.
You have quite a few options. Would you rather leave early in the morning because trains run every two hours from 05:35 ?
I could leave in the morning.
How many tickets please?