The Clocksville Express is a short-term event in which the player moves on a train from station to station.
To reach a station, you should collect tickets in match-3 levels. At stations, you can either exchange the tickets for a reward or get extra tickets to reach the next station quicker.
The event is time-limited, but if you complete all the stations before the event ends, you can play the event again. If you do not reach a station and claim a prize before the event ends, your tickets disappear.