LED On/Off and Color Control Mechanism

Should be a piece of cake.

Use this 5050 RGB LED Strip and just cut to size where you'd like the strips.

You can turn on individual colors by selecting which leads to energize.  For red, green, or blue, it's just one lead and common with 12V.  A simple relay control like my Insulated Track Signal Driver, Rev. 2 will complete the package.  Well, you will also need a 12VDC power supply for the LED's.

Thanks GRJ. I did not know that you could trigger individual colors by using the different leads. I have to play with that once I get a bit further on my layout, BRATS RRv2.

Gerry

The strip I linked has four leads, a common and three leads for the three primary colors.  By combining the power to more than one of the three primary color leads, you can generate the whole rainbow.  For red and green, it's dirt simple, common and either the red or green wire will give you all red or all green LED's on whatever length of strip you cut.

You can also find the addressable LED strips, where each LED on the strip can be programmed to be a different color.  As you can imagine, you need a microprocessor or other sequencer to do that trick.