If the artwork is on train tracks, is it still called street art? Rail art? Either way, we’re loving this series by Portuguese artist Artur Bordalo in which he cleverly converts the horizontal lines of train tracks into a canvas. The series, which has been popping up on railways throughout Portugal since early this year, often use bright, neon colors which create a nice contrast between the dull gray rocks and tracks. Each work is accompanied by subtle titles that can be playful but also harbor critical or cynical undertones.

The artist also goes by the moniker Bordalo II, an apparent ode to his grandfather whom he saw “painting the city of Lisbon.” You can see more of his work on his website or Facebook page.