I've always wanted to create one and finally i found out how to. I got three images and stiched them together to make panorama, rotated it 180, then polarised it. Then blurred and fixed up any rough spots (there always is a couple).
This one i used background image design entitled Jellyfish by linn Olofosdotter, check out her amazing designs
here, then added the train tracks but using magic eraser got rid of some of the colour creating a mad effect, then i found a image of millenium train (couldnt be bothered finding one without the graffiti on it HAHA but i think it enhances the image a little right? Interesting fact, once i changed the exposure you cud see the train driver sitting inside) saturised it and paint bucketed yellow, and then i got a photo of Central, saturised, contrasted, filtered a spherize warp and paint bucketed with a light grey.