Rusty, who wants to compete in the world championship railway races, has lost self belief because Greaseball and Electra have been taunting him, and his coach, Pearl has dumped him for faster locomotives.
Then, as the Starlight Express, joins, he sings the tune of Only You, a theme not yet heard at this point.
Rusty then comes back with the Starlight Express theme, to say he doesn't understand.
Rusty still starting alone, but after twice calling out to the Starlight Express and discarding his helmet, the actress playing Momma would enter at the back of the Stage portraying the voice of the Starlight Express.
And for the 2022-23 season, the theatre installed a speciality lift under the stage, in which Rusty would be elevated into the air during the number and engulfed by drones before being lowered for the ending.
And for the 2023-24 season, Rusty at the song’s climax would expose a Disco ball in his chest which would dramatically reflect off the lightning.
When they both sing the 'Only You' theme, Rusty is lifted into the air amongst the stars, coming down to pick up his helmet at the end.