Whiff is a grubby green tank engine who collects refuse. His main task is collecting garbage and scrap, which explains his dirty appearance and smell.
Whiff is cheerful and optimistic. He enjoys his job of collecting garbage. He doesn't seem to care what the other engines think about him: either that or he is oblivious to their opinions. Despite that, he is friendly and always does his job well. He is somewhat naive, as he didn't realise why the other engines tried to avoid him so much. However, in Misty Island Rescue, he is shown to know about Sodor's history, since he knew about the tunnel connecting Misty Island to Sodor.