The Starlight Express is a god-like character within the world of the trains, a legend that disillusioned young steamers such as Rusty no longer believe in. However it is the appearance of The Starlight, at Rusty's darkest hour, that gives Rusty the confidence to pick himself up and fight back, going on to win both the race and the affections of Pearl.
Within the framework of the "Cinderella" story, The Starlight Express is Rusty's "Fairy Godmother" whose appearance changes his fate.
This is a contentious issue, fans' opinions being broadly split by which production they are most familiar with.
In the London staging of the Starlight Sequence, Rusty is joined onstage by a shadowy figure who sounds, and looks, much like Poppa, but who answers Rusty's call to The Starlight. He stands right behind him and touches his hands. In the Bochum production however, Rusty is alone and just hears a voice. In the UK Tour, Rusty is magically levitated, while The Starlight sings upstage, almost invisible.
Generally speaking, fans of the London show are of the opinion that The Starlight doesn't exist as such, and it is Poppa who pretends to be The Starlight in order to encourage his protegé. German fans are more likely to believe The Starlight is a separate entity, also played by the same actor who plays Poppa, since he is never seen.
Where Is Poppa, Then?
Should you be curious (and have excellent night vision or happen to be at the right angle) in the Bochum production, The Starlight Express is sung by Poppa from the upper stage right bridge anchor point. He is entirely unlit but from certain angles his shadow can be seen among the lasers. He has a direct eye-line to Rusty from this point.
The presence of "The Starlight Express" is announced by the magical effects of the enormous star field filling the performance space, shooting lights, lasers, and in the original London production, the stars forming a constellation in the form of an express train. However this was replaced in 1992 with stars forming the shape of a star.
Broadway Appearance of The Starlight Express
The second production of Starlight Express, Broadway in 1987, gave the show its first major overhaul. One idea that was trialled but later dropped during the previews was that Rusty literally turned into the Starlight Express. This was achieved by a costume change, into a smart black and silver version of his "rusty" costume. As he appeared for the final race, nobody recognised him, even Control asked "Who are you?" to which he replied "The Starlight Express".
This concept, while cementing the transformation part of the Cinderella story, had its practical drawbacks. Rusty had only moments in which to make a full costume quick change, which Starlight Express costumes do not make easy. Also the costume was somewhat nondescript, being principally black with shiny studs, much like the Gang costumes. Also his regular costume was quite dark so the removal of the rusty patches did not have a big impact on his appearance. Very few photos exist of this costume in performance.