| 1 | Fahrstuhlmusik | 4:52 |
| 2 | Travel / Voyager | 4:29 |
| 3 | Metropolitan / Metropolitain | 2:58 |
| 4 | Spacecadet / Weltraumkadett | 4:19 |
| 5 | Machi no Ongaku | 3:29 |
"Underground/Overground" (title taken from the English lyrics for the track "Metropolitan") is essentially composed of tracks from the earlier "How to Measure the World" EP, with the removal of the title track and addition of two others. The first, "Machi no Ongaku," was a newly recorded track based on a mostly unfinished one from the "International" sessions. The second was the version of the "International" track "Weltraumkadett" (on varying editions titled "Spacecadet") heard in that song's music video, albeit mixed differently with various languages. Also of note is the somewhat expanded version of "Travel/Voyager" featuring additional percussion and synths at the end of the track which were not present on the original mix included with the "How to Measure the World" EP. Underground/Overground was released in three editions; one in English, one in French, and one in German. On each release, the title and lyrics of "Machi no Ongaku" and the title of the instrumental "Fahrstuhlmusik" are written in Japanese and German respectively regardless of release, although the German and French releases feature the title of "Machi no Ongaku" in Japanese characters rather than the Roman ones seen on the English release. The German edition features the English version of "Travel" and the French version of "Spacecadet" retains most of the English lyrics, with only the second verse and chorus occurring in French.