The following text is taken without permission from 'Gaenzl's Book of the Musical Theatre', by Kurt Gaenzl and Andrew Lamb, copyright 1988 to Kurt Gaenzl and Andrew Lamb, published by Bodley Head.
Act 1
'This musical story about trains is set on the sort of toy train layout that everyone would like to have in their lounge, but which only governments can afford. Its characters are the locomotives and carriages which make up the trains, and the first to which we are introduced are the aggresively macho engine, the Pacific Daylight, commonly known as Greaseball, and his gang of 'Rolling Stock'. Greaseball is the finest and fastest diesel locomotive in the world, the defending speed racing champion of two hemispheres, and well and truly too big for his pistons. He takes a cruel delight in making fun of little Rusty, the steam engine who works the sidings ('Taunting Rusty').
Rusty is a sad little engine: he's falling to bits, out-of-date, and he lives on hopeless dreams of steaming gloriously along at the head of his carriages, leading the other engines at racing speed ('Call Me Rusty'). He wants ever so much to enter this year's championships. The carriages - Ashley, the smoking car, Buffy, the buffet car, Dinah, the dining car and the brand spanking new and decorative Pearl - find him a sweet fellow but think his pretensions to racing are ridiculous ('Rusty, You Can't Be Serious'). There's no way that they can join behind him as his partners in the racing. After all, what a carriage needs is 'A Lotta Locomotion', and that Rusty just doesn't have. They're much keener on teaming up with Greaseball, who takes every opportunity to flex his cam-shafts in public ('Pumping Iron'), but Dinah has first claim there - she will be the champion's coach for the big race.
The passenger coaches' noses go up in the air when a freight train approaches ('Freight'). Rusty is the locomotive, and behind him are three box cars (Rocky I, Rocky II and Rocky III), a brick truck (Flat-top), and aggregate hopper (Dustin) and a little red caboose (CB). Freight and passenger trains are both convinced of their own supremacy, but the time for banter is over when Control - a disembodied voice - announces that the championship racing will begin in ten minutes.
One by one the challengers for the title are announced: France's Sudest (Bobo), Italy's Settobello (Espresso), the German Weltschaft, Russia's Trans-Siberian Express (Turnov), England's Advanced Passenger Train (The City of Milton Keynes), the Japanese Shinkansen Bullet Train (Hashamoto), Greaseball...and Rusty. The last entry to arrive is an even bigger surprise. Electra is an electric train ('AC/DC'), an androgynous streak of power out to prove the superiority of electric power. Diesel, electricity and steam all join together in a challenging ensemble ('You - You're Overloaded').
Each engine now has to be hitched up to a carriage with which to compete in the race. Greaseball and Dinah are the first pair, and gradually the most impressive locomotives pair off with the most appealing carriages. Rusty hopefully approaches Pearl. Pearl has dreams of pairing up with a steam train, one whose whistle she hears in her dreams ('He Whistled At Me') but, as she gently tries to explain to him, funny little Rusty just doesn't live up to her dreams and she will not hitch up to him. Suddenly an electric minion sidles up. Electra's coach has a headache and he has chosen Pearl to be his partner instead. Although electric current does nothing for her, she agrees to go, and Rusty is left without a carriage.
The first heat of the racing begins. Greaseball manages to come out in front, but only by foul play, and, when Dinah chides him with cheating ('Wasn't Fair'), he angrily disconnects from her and zooms off, leaving the disconsolate Dinah to the opportunistic consoling of the creepy little caboose ('There's Me').
Off in the siding, big old Poppa steam train is singing the blues ('Poppa's Blues'). When the dejected Rusty steams by, he tries to cheer him up. It's no use moping. If Pearl won't race with him then he must hitch up to something else. He points to peeling old Belle, the sleeping car. Rusty isn't too keen, even though the lady in question is long on experience ('Belle the Sleeping Car'), and it takes all Poppa's extolling of the virtues of faith in the 'Starlight Express' before Rusty find courage enough to turn up on the starting grid with Belle behind him to race against Weltschaft and Electra.
In another roughish race, the electric train comes out a logical winner and Rusty, even deeper down in the mouth than before, returns to his friends with his confidence in steam and the Starlight Express gone up in smoke. Poppa chides him ('Boy, Boy, Boy') for his lack of faith: steam is still the greatest and, to prove his point, he steps in to replace the unpunctual British train in the final heat with big fat Dustin the aggregate hopper hooked up behind him. And Poppa does it. He leaves the French and Russian trains behind him and struggles over the line the winner. But his big effort has been his last, for pulling the hefty hopper has blown his gaskets. There is no way he can take part in the final: Rusty must take his place. Now Rusty has to believe he can do it. He can do it with the help of the 'Starlight Express'.
Act 2
The rights and wrongs of Poppa's place in the final being taken by the eliminated Rusty get an airing in 'The Rap', as new partnerships are evolved. Greaseball, having dumped Dinah, takes up with Pearl, leaving the dining car to wail tearfully in country style of her being 'UNCOUPLED' as her sister coaches attempt to comfort her ('Coaches' Rolling Stock'). She will have to be content to be hitched up to the electric train. CB is going to be teamed up with Rusty. He will be a nice, light little carriage to carry, but the red caboose is a two-faced twister who is plotting with Electra and Greaseball to sabotage the steam train's chances ('CB').
The final is held on the uphill track, and it is quickly a two train race as the red caboose plies its brakes when it should be urging the engine on. But Greaseball and Electra dead-heat and a rerun is ordered ('I Was Robbed'). Rusty's whining complaints are silenced by the jiving Rockies ('The Right Place at the Right Time') and it needs another dose of inner Starlight Express ('I Am The Starlight') to get the little fellow confident enough in his abilities to try again. This time the race is to be on the downhill course and Rusty pairs up with the heavyweight Dustin. Dinah has deserted the electric train who can't whistle at her, so CB is back in harness, teamed with Electra. This time, pushed by the lumpy Dustin, while Greaseball and Electra indulge in their own private battle, Rusty makes it home first.
Electra is terminally mortified in defeat ('No Comeback') and Greaseball and CB are all cracked up ('One Rock'n'Roll Too Many') but Rusty goes off, without completing his lap of honour, to look for Pearl who has finally got round to realising that Rusty is her engine ('Only He (Has The Power to Move Me)'). Greaseball also comes to his senses as Dinah proves faithful to his battered chassis, and brightens when Poppa tells him that he may even survive - converted to steam. The whole company joins in praise of steam ('There's a Light at the End of the Tunnel') and its future second coming as the show ends. Old-fashioned craftsmanship has triumphed over modern technology.'