“I like trains” is a repeating line where the subject is often saying “I like trains” before subject is ran over by a train. He is also referred to as Michael Kirkland in Yorkshire due to his vast knowledge of trains. He was voiced by the legendary Edd Gould (I'll never forget you, man!), who sadly passed away in March of 2012. Because of this, one last usage was made in asdfmovie9. Later on in the series the subject stops getting run over by a train and anyone near would be run over.
This meme came from the asdfmovie2 by YouTuber "TomSka", and has been featured on nearly every asdfmovie since.
Appearances outside of asdfmovie
The I like trains kid appeared in his own song also made by TomSka which was called "I LIKE TRAINS!"