I started with my camera on the action setting, so the camera knows I'm trying to capture something fast and it selects appropriate settings. What's useful about that is being able to check the settings the camera picked because it gave me a good place to start when I went to more manual setting. The camera started at a shutter speed of 1/800 sec for action shots. After a few clicks, I realized I had the camera set at ISO400, so I switched to ISO 100 and started slowing down the shutter speed because I decided it would be fun to try and capture the action in my shot instead of trying to "freeze" it. I also started shooting in shutter priority mode, letting the camera pick the aperture. Here's a shot from after those initial changes:
ISO 100, F5.6, 1/500 sec. (remember the camera started at 1/800 sec.)
At this point, I just kept dropping the ISO to get the motion effect that I wanted, from 1/500 to 1/200:
ISO 100, F11, 1/200 sec.
Then from 1/200 to 1/124:
ISO 100, F10, 1/124 sec.
Then from 1/124 to 1/100, where I got this shot. I was also really hoping to get the photo I wanted with the RED train because I thought it would be the best contrast and create the most interesting photo. I was pretty happy with this one:
ISO 100, F14, 1/100 sec.
I took a few more shots of the following trains, but eventually got bored of standing in the same place. By the time I got done, I had taken about 20 pictures in this one spot. It wasn't until I got home that I decided this very last shot with the yellow train was my favorite. The camera settings are the same as the one above with the red train, but by zooming out, the train is placed in the setting better. Also, as it turned out, the yellow provided a better contrast with the blue sky and the bright red roof in the building behind the coaster. I think I have a winner. :)
ISO 100, F14, 1/100 sec.