There is no train station at Bergamo airport, but you can get a bus into the city and from there you will find that regular trains run to Milan (one hour journey time), Lecco, Lake Como and Brescia as well as on to Verona and Venice.
Trains to Milan run hourly and you can check the latest fares and schedules on the Italian Railways website. Some trains run to the main Milan railway station, Stazione Centrale, and others to Stazione Porta Garibaldi.
If you trying to get to Milan or Brescia from Bergamo airport another option is to catch one of the regular coaches which will take you directly there.
There is no left luggage office at the railway station, but there is a left luggage facility at Bergamo Airport.
For more extensive rail links, Milan Railway Central Station is served by Trenitalia and operates regular trains to most major Italian destinations including Rome, Bologna and Florence (an hourly Eurostar train connects these towns and the journey to Rome takes around four and a half hours.)
The Tourist Information Office is in a small shopping arcade located at platform level: look for its "APT" sign. The ticket hall is on the floor below where there are ranks of automatic machines and steps down to the Metro are just outside.
Before boarding your train you must validate (stamp) your ticket in the special yellow box which is located on the station platform and in the foyer. Once stamped the ticket must be used within six hours for journeys of up to 200km or 24 hours for a journey over 200km. If you do not validate your ticket you could incur a hefty fine and boarding a train in Italy without a ticket will also incur a fine of at least €30.00.