Here is a circuit diagram for track powered marker lights. You will need to adjust the variable resistor until you get the right voltage for your capacitor.
The marker lights will stay on for a while with out track power. The lamp is for interior lights and can be left out if you want.
If you need to find some parts I recommend using Digi-Key their website is http://www.digikey.com
If you need to find some parts I recommend using Digi-Key their website is