Jared Johnson, the composer of the Tube Craft soundtrack, made it avaible on Soundcloud and Bandcamp.

It consists of five trakcs (1 per 4 courses in-game), called Spark, Perimetric Test, Caldera, Tube Master and Herculean.

It sounds retro and futuristic at the same time, which perfectly fits the game. If you enjoyed the soundtrack, consider giving the game a shot !