Wiring a Train Switch

[Athos]

I want to do a train layout where someone can push a button and it will run the train one time around the track and then stop until the button is pushed again. So the public could play with the train during a show.

Has anyone does this? And if so, can you explain how I would do it?

Steve

[dr_spock]

What type of train do you plan to run? Is it Power Functions? 9 volts? 4.5 volts?

How big is the track?

Do you want purist LEGO solution? Is it ok to have non-LEGO solution?

[Rail Co]

I'm no electrician or electronics engineer but I assume you would have to set a timer that clocks how long the train should run for before cutting off power to the circuit.

-RailCo

[dr_spock]

I'm no electrician or electronics engineer but I assume you would have to set a timer that clocks how long the train should run for before cutting off power to the circuit.

-RailCo

Timer is good if you want to run the train for a certain amount of time and where it stops is no concern.

You can use sensors if the train has to stop at the same spot or change directions or the speed could vary based on the charge remaining in the batteries of Power Function trains.

[John Hill]

There are a number of quite simple things you could do depending on what type of trains you are running.

[Athos]

We run 9V trains at our displays. Though I also have several of the new ones.

Steve

[Duq]

With PF this will be very difficult. For 9V you can do it with an RCX and a light sensor. I've run a similar setup, only with a timer instead of a button.

RCX Train Control by Duq, on Flickr

[John Hill]

Suppose you want a very simple sequence such as the train standing at a station starts and runs around the track before returning to the station and stopping until the button is pressed again, this would be a very simple thing to do with not much more more than a simple push button.

First you must electrically isolate one or two sections of track from the others and the easy way to do that is to insert a layer of insulating tape or even paper where the rails join.

Connect the power controller to the remaining track in the usual way and check that the train will run around the track and that it stops when it comes to the isolated section. Connect a push button switch between the main track and the isolated section and check that pushing the button causes the train to start.

It probably took me longer to type this that it would to actually do this.

[Brickthus]

Not too difficult with 9V or 12V track, if you isolate a section of track.

For the public interface, I would use a doorbell button from a DIY/hardware store. Much longer life than LEGO parts under public hammering!

Mark