This was done by putting the camera on a low tripod (actually I used the Clamperpod stuck on the thick, square leg of an old telescope tripod), setting it to bulb mode and manual focus, trying a couple different apertures, and using a remote shutter release. I'd back the monorail up enough to give me a few seconds, then as it came into view (not through the viewfinder - too low - but composing ahead of time and knowing when it's be in frame) I'd open the shutter for 2-2.5 seconds, and just before closing the shutter, I'd fire my very old flash unit from my 35mm (loose, not attached to a camera.) The first photo, I shot it directly at the scene and it was completely blown out. After that, I shot it in the opposite direction, and there were enough reflections to give a ghostly image on the monorail, with a trail from its green headlights. When all was said and done, I did a little color tweaking and cleanup, and voila.