Two Wheels Good

S19 E14: Bertie, Thomas and Spencer get into a debate about how many wheels is best. Bertie has four wheels, Thomas has six and Spencer is very proud of his twelve. But when Spencer breaks down while taking the Duke and Duchess to Callan Castle, Thomas must transport his passengers instead. Then Thomas finds the track blocked and Bertie takes over. And when Bertie has a flat tyre who should turn up, but the Thin Controller on his bicycle. Surely the Duke and Duchess can't ride to Callan Castle on his bike! Luckily, the Thin Controller has a better idea about how to help.