"Train of Thought" is a song by the Norwegian synth-pop band a-ha, released in March 1986 as the fourth single from their debut studio album, Hunting High and Low (1985).

The lyrics for this song were based on the existentialist authors and poets Gunvor Hofmo, Knut Hamsun and Fyodor Dostoevsky – Pål's favourites at the time.

It was not a pop hit in the United States, but a 12-inch single featuring a remix of the song appeared on the Hot Dance Club Play charts.

It originated as Patterson's student film at CalArts called Commuter, which went on to influence a generation of MTV videos.

Most of the video was the old animated footage, interspersed with live parts with a-ha filmed during a break in the band's tour.