We strongly encourage the reader to review and test the individual devices listed in the Device Pages.  As you'll come to find out, the trolley circuit diagram is not much more than the individual devices all combined together, working as a single unit via the Trolley Software.

Basic instructions:

1. Click the image to the right.  For best resolution, download the image and then open it with your favorite picture viewer. 

2. If you're using a tablet or phone, try installing the google photos app.  The schematics should open up in the mobile app and let you zoom in for higher resolution. 

   • apps.apple.com 

   • play.google.com

3. Also, here's a link to all the individual schematics: [click here]

4. Crossing signal lights:  Note that the program is using digital write on the pca9635 LED driver.  Since digital write sets the pin to either 0% or 100% duty cycle, resistors are required. 

5. There are many ways to obtain a 5 volt source for the electronics.  Unless you're very good at calculating amperage usage, do not connect the electronics to the 5v RPi pins.  Instead use a separate 5v source, such as a buck converter attached to the 12v dc train supply. 
   Buck converter: [click here]