I have never been real happy with the lighting in the Aristo RDC.  I changed the window material to get a tinted look, and put in tube bulbs from Walthers to get better lighting, but this has not been a satisfactory solution.  Recently, I have been reading the Aristo Forum and have been corresponding with a member who lives in New Jersey (Emil Tancredi) who put both an interior and minature fluorescent lighting into an RDC. Check out the Aristo site under Kitbashing to see pictures of his creation.  While the interior is a neat improvement, and may be a future project, many RDC's had such dark tinted glass that you could not see much inside even at night. However, the ability to produce real fluorescent lighting in a model which is what the prototype used caught my attention.
    I bought a kit from Cat# Fl-120WH which is a Cold Cathode Fluorescent light and inverter.  The tube is 12 inches long and is .45" in diameter.  It comes in a plastic housing and is easily mounted with tape supplied in the kit.  I also bought their 5 Volt inverter since I wanted the light to come on at low track voltage rather than the 12 volts that the kit inverter uses.  The inverter is polarity sensitive so electronic magic has to be performed so that the tube lights in both forward and reverse and the inverter does not blow.
I went to Radio Shack and bought a voltage regulator (Model # 276-1770) which is rated from 0 to 35 volts, and puts out 5 volts for the inverter. I also bought the heak sink kit (Model # 276-1368) because I knew that this component would get real hot during normal running.  Make sure you buy the special heat sink lubricant which insures the best heat transfer to the sink from the component.  To keep the polarity the same for the inverter no mater what the track polarity is, I bought a Full Wave Bridge Rectifier (Model # 276-1152). This is where the magic happens, as usually Bridge Rectifiers are used to convert AC voltage to DC voltage.  In thus case, the Bridge Rectifier will keep your DC track power power directionalized so that positive and negative voltage does not change to the inverter regardless of the direction your RDC is running.
    Check your track voltage for polarity with a meter and hook up the leads from the track power for the RDC to the two AC terminals of the Bridge Rectifier.  Run the positive and negative leads from the Bridge Rectifier to the Input (+) and Ground (-) leads on the Voltage Regulator. Then run two leads from the Voltage Regulator Output (+) and Ground (-) to the corresponding (+) and (-) terminals on the inverter.  Hook up the leads from the Fluorescent tube to the remaining leads on the Inverter (it does not matter which terminals you use as there is no polarity here).  Apply track power and your tube should light at 5 Volts (slow speed) and continue with the same brightness at all speeds, even when you change directions.  See the picture below to understand the wiring of this circuit. Make sure you keep the polarity correct, or you will blow your components and your inverter.
    This same technique can be used to light the interiors of your streamline passenger cars, which is far more realistic than incandescent bulbs that dim and flicker when the train starts up or slows down.  Contact Emil through the Aristocraft forum if you have any questions.
Components for Fluorescent lighting.
Red/Green twisted wire at left is to track power.Small component at left bottom is the Full Wave Bridge Rectifier. Component at the top is the 5 Volt Voltage Regulator. Circuit board at right is the Inverter. Fluorescent tube is hooked to pins on the right of this circuit board. If you carefully follow the instructions that come with each component, and keep the polarity correct, you will successfully have Fluorescent lighting in your RDC or passenger coach.  Red wires are all positive leads, and blue or green wires are all negative leads.
These are Emil's RDC's.  The one at the top has factory lighting, and the one below it has the new fluorescent lighting.