A new event is available in the app daily. While everyone gets the same event, the event city is randomly selected each day from those which are visible on your map (whether you currently have them unlocked or not). The event city is marked on the map with a tan "!" logo over the city dit as well as listed in the event tab from the Pocket Trains main menu.
Events run from 12:00am to 11:59 pm each day. To complete the event and receive the reward, all deliveries must be completed and recognized by the app during this time frame to count. If you send a train carrying event cargo and close the app before it arrives you will need to reopen the app after arrival but before the event ends to get credit.
The number of jobs required for completion will also vary from event to event. Some events require cargo to be delivered to the event city while others require cargo to be delivered from the event city. The details for each event are listed in the event description. In the stations, event cargo are listed in blue font to help distinguish them from non-event cargo. Not all cargo to and from the event city will count towards the event.
There was a bug in a previous version causing the city name for some events not to display properly in the event description. This is resolved in the latest version.