Toad worked with Oliver on the Great Western Railway before being threatened with the prospect of scrapping. Oliver, Toad and an autocoach named Isabel ran away for the greener pastures of the North Western Railway, but Oliver ran out of coal en route. Luckily, they were rescued by Douglas and brought back to Sodor. In the Railway Series, Toad asked to be Douglas' brake van as a show of thanks. In the television series, Toad remains as Oliver's brake van.
When S.C. Ruffey began to start a trend of disrespecting the engines, Toad had the idea for Oliver to show him and his lieutenants the error of their ways. This turned out better than expected, for Oliver pulled S.C. Ruffey apart and won back the respect of the trucks.
In the television series, Toad was tired of always going backwards and wanted to be a leader for a change. The trucks decided to teach Toad to be careful what he wishes for by breaking away from Oliver on Gordon's Hill and as a result, he crashed into some level crossing gates, narrowly avoided Gordon and James and stopped by taking a plunge into a muddy pond. Afterwards, Toad decided that always going backwards was not so bad after all.
While Gator was on Sodor, he once took some of Oliver's trucks with Toad, who kept insisting that Gator should stop and relight his lamp. After being briefly taken off the train after forcing them to stop with his brakes, Toad had the "bright" idea of giving Gator one of his lamps to replace his broken one. This idea worked, and Gator thanked Toad once they had finished their journey.
By Toad's Adventure, Toad had become bored of repeatedly hearing the story of Oliver's escape, and longed for an adventure story of his own to tell. His wish was granted when he went to work with James, who ran much too fast and hit a fallen branch on Gordon's Hill, uncoupling his trucks. Toad managed to stop the trucks, and prevented a crash with Thomas and Percy. When he returned to the Yard, he told a disbelieving Oliver all about it.
Toad eventually began to sing during his journeys with Oliver, which the Western engine liked at first, but quickly got fed up of listening. Later, as they were passing Bluff's Cove, Toad spotted a whale stranded on the beach and tried to tell Oliver, but Oliver thought Toad was joking. But later that day when the two passed the same area again, Oliver saw the whale and apologised to Toad. They informed the Sodor Search and Rescue Centre, but after a few attempts at moving the whale proved unsuccessful, Toad had the idea of using a flatbed to transport the whale to Brendam, where Cranky gently placed the whale back into the water. Now whenever Toad passes through Bluffs Cove, he remembers his friend, and sings about him.
In Sodor's Legend of the Lost Treasure he, along with Oliver, helped to build the new Harwick Branch Line and attended the line's opening.
Toad is a polite, gentlemanly, and optimistic brake van. He is also somewhat imaginative and a bit of an optimist. Toad minds his manners well and always quick to refer to the engines as "Mr.", "Miss", or "Sir". He escaped from scrap with Oliver, with some help from Douglas. Toad is very loyal, keeps Oliver's trucks in order, and has his best interests at heart. He has a cunning streak within him should the trucks cause any particular bother and does like fun when it comes his way, but he is typically calm, obedient, and content in his work.
Toad is based on a Great Western Railway 16-ton brake van. Early vans were just 10 or 16 tons weight, but this gradually increased to 20 and 25 tons.
Toad is painted grey with "GW 56831" written on his side in white. Before being repaired in Enterprising Engines, and in an illustration portraying him before Escape from the subsequent book, Toad was painted brown. In the Railway Series, his face is the same colour as his bodywork, but in the television series he has a light grey face.