Back Up Brewster / Chief Wilson

S4 E109: Brewster is learning to use the mega-chug crane, but his training time is cut short when they are called away to fix some damage in a mine tunnel. As they cross the old rickety bridge it collapses, leaving Zack stranded on the other side. How will they ever reach him? Brewster has an idea. / Wilson takes a test to assess his new Chug Patrol skills, but he forgets something important and fails. Later when a real emergency arises, Wilson handles the situation perfectly and gets Old Puffer out of trouble. Jackman is impressed - maybe Wilson will even make chief one day.