Rubble is an intelligent orange haul truck who helped Bob build the amusement park. He tends to be worried that he is not fast enough. It was implied he'd return from being a one-time character to a recurring character in Bob the Builder: Ready, Steady, Build!.
Rubble is generally very smart but sometimes worries about speed. However, he learns to work slowly and take his time without rushing. He is also very kind and friendly.