It is essential to make use of diagrams in the design of model train circuits because a diagram can help you to do the job with no errors and in the unfortunate event of a faulty circuit, you can go back and refer to the diagram to diagnose the issue. Designing own circuits is recommended only for advanced users because thousands of diagrams for circuits can be found on the internet. Make sure that the color codes for resistors, flashers and electrical supply etc., are accurate from user comments and your own common sense.