Chuggington StackTrack is a track system that allows layouts to expand up. Based on the "Chug Patrol and the Rescue at Rocky Ridge" Chuggington episode, this playset allows young engineers to recreate the exciting adventure. After receiving her new rocket boosters and speeding a little too quickly through Rocky Ridge Mine, Koko gets trapped in a crevice under a pile of rubble. Chug Patrol Wilson must come to the rescue, using his new Chug Patrol skills. He bursts through the entry barriers, barrels through the mine shaft, crashes through the archways, and must avoid the tumbling boulder on his way to save the day.