Act I
Mr Perks, the Stationmaster, remembers how the story began, in a family home in London one Christmas (“Prologue: Christmas is Here!”). The family, Father, Mother, daughters Roberta (Bobbie) and Phyllis and son Peter (who has opened his gift, a toy railway) are the model of a happy family. Ruth, the maid, tells Father that two gentlemen have arrived to see him. Father goes to meet them, and Ruth returns to tell the children that Christmas is cancelled (“You Can Never Return”).
Mother and the children are then discovered at Charing Cross Station, ready to depart to a new life in the country. Mother will not tell them where Father has gone, but not to worry – they will still be “Together.” At the end of the number, they arrive at their new home. It is cold, damp, dark and there are no servants (“Together” Reprise).
Next morning, the children find a railway line nearby and watch as trains run by. They think it looks like a great green dragon and, as they wave, they ask it to take their love to Father, wherever he is. In the last carriage of the train they see an Old Gentleman, waving back at them.
They arrive at the station and meet Mr Perks, who tells them of the wonder of the railway and introduces them to the other villagers (“All On Time”). That evening, Mother is taken ill and Doctor Forrest tells Bobbie that she must have certain foods to make her better. Mother tells Bobbie that they cannot afford this, but Bobbie, Peter and Phyllis come up with a plan to ask the Old Gentleman in the train for help (“You Might Make A Friend”).
Perks brings a package from the Old Gentleman, containing all the food they need – and more. Mother is angry that they have asked a stranger for help and sends them to the station with a thank you letter for the Old Gentleman.
At the station they meet some of the local children, and after initial hostilities, make friends (“Posh Talk”). A train arrives and a strange foreigner alights, clearly lost. Bobbie sends Phyllis to get Mother, who is able to converse with the man in French. She tells the villagers that Mr Szczepansky is a Russian dissident writer who has escaped from a gulag and has come to England to find his wife and child, who he believes are there. She takes the Russian man to her cottage where he can recover from his illness (“Russian Lullaby”).
The children want to help Mr Szczepansky become reunited with his family, so they write to the Old Gentleman asking for his help (“The Railway Children”).
Mother sends the children on a picnic, but Bobbie returns to find Mother crying. The thought of a picnic has made Mother remember the wonderful times they all had with Father, and after Bobbie has left, she longs for her husband (“‘Til The Day”).
Picnicking on the hillside, the children witness a landslide, which blocks the line. Realizing that the train is due and will crash if they do not intervene, the children create red flags from the girls’ red bloomers and wave them at the train as it leaves the tunnel. The train stops, just in time.
Act II
Act Two opens with the entire village celebrating the children’s bravery at an award ceremony where the children receive commemorative watches (“A Once-In-A-Lifetime Day”). As the crowd disperses, Mother thanks the Old Gentleman (who is a Director of the Railway) for his help when she was ill. He asks to see Mr Szczepansky, announcing that he has found the Russian’s family; they are living in Oxford and they can be reunited that afternoon.
As the family go to help the Russian pack, Bobbie asks the Old Gentleman how he is always able to help. He explains his philosophy (“Busy Dreaming”).
Weeks later, the children watch a group of grammar schoolboys on a cross country race (“Paperchase Ballet”). They notice that one of the boys entered the railway tunnel, but hasn’t come out the other side. They enter the tunnel and find him, injured by the trackside. Bobbie sends Peter and Phyllis back to get help (“Nothing To Fear”), and, once home, Dr Forrest tells Bobbie that Mother has gone to meet a relative of the boy, Jim. Peter and Phyllis arrive with some medicine for Jim, wrapped in newspaper. Bobbie notices a news story and, starting to cry, tells her siblings to leave her alone.
Mother returns with Jim’s grandfather: none other than their dear Old Gentleman. Sending the Old Gentleman upstairs with Peter and Phyllis, Mother asks Bobbie why she is crying. Bobbie shows Mother the newspaper, which carries a story of Father’s imprisonment on spying charges. Mother is finally able to tell Bobbie the whole story of how Father has been wrongfully imprisoned and Bobbie asks the Old Gentleman for help.
The Old Gentleman, sure of Father’s innocence, teaches Bobbie a poem penned by her friend Szczepansky. Still keeping Father’s fate from Peter and Phyllis, Mother and Bobbie return to London to campaign for Father’s release (“One Voice”).
His broken leg now healed, Jim leaves the Three Chimneys cottage to return to school, but not before promising Bobbie he will write and gently kissing her. The children go to see the railway again, but, this time, notice the Old Gentleman and all the other passengers waving to them (“Who Knows What You’ll Find”). Bobbie, emotional after Jim’s affection, sends Peter and Phyllis home and sets out on a walk alone (“Nearly Autumn”).
She meets Mrs Ransome, the postmistress, who tells her of a telegram that has arrived for Mother. She tells Bobbie to rush to the station. At the station, a crowd has gathered, and everyone is in a state of high excitement. A train arrives and, as the smoke clears, Bobbie sees a figure. It is her Father. The family, having received the telegram, arrive at the station to be reunited at last (“Finale”).