How to Run Trains in Model Train Layouts

"On behalf of Expert Village my name is Bob Lanning. I'm here to tell you about making a train diorama in HO scale. Now, this train here represents the Arizona extension train that was going into the smelter to pick up ore. The reason it goes backwards is there's no way we can run these around in a circle. We have a sensor at each end of the trains run and it reverses the polarity. He's backing in to the smelter area and then when it comes back out it'll go all the way to the Josephine tunnel. We use little photo sensors, when the train blocks the light, it changes the polarity and the train turns around and goes back in the other direction. Our main lines are run by a regular transformer. We have many, many automated lines through so when we operate the diorama for visitors they see that things keep moving. Now this train is coming out of the smelter and it reverses by going over an optical sensor which reverses the polarity so when it gets to the other end now it'll reverse and come back in to the thing. That's why the, it goes the right direction in one way and it has to back up, there's no way we can turn the train. There's many areas on the layout where we run the optical sensors to move the things back and forth. The main lines are run off the transformer and they just run as we wish."