This week, I look at installing light-bars into 2 Amtrak Phase IV Superliner cars. We have a coach and sightseer car to upgrade.
Verify the light bar works
This is a simple first step before I get started. Simply clip power from a test track to the jumper wires at the end of the strip.
Disassemble the car
You need to remove 6 screws from the car (3 at each end)
- 2 screws holding the coupler in the coupler posket
- 1 screw attaching the swinging drawbar to the underbody of the car (small fiber washer on this screw)
There are 3 clips per side holding the center section of the car to the outer body
- This step is a little tricky as it feels like something might break
- The shell will come away from the rest of the car
Attach the light bar
The car is prewired for the light bar. there are 2 pair of contact strips at each end of the car. Each strip has a J-hook at the end that will clip to the bus wire connection point on the light bar.
No reason not to put the car on a powered test track again to ensure everything is connected in good order and the bar is lighting up properly.
Close it up!
Put it back together the way it came apart. You do remember how you took it apart, right?
Review of the light bar
The design is simple enough to understand.
- Bridge rectifier
- A couple of tuning resistors to set the LM317 voltage output
- 4 clear LEDs
I have a concern about the design as it appears that the circuit is tuned to match the forward voltage required by the LEDs, but I see zero evidience of any current limiting resistors. The LEDs are in parallel also. I might be missing something, but it’s a risky game to try to match the output voltage of the regulator to the forward voltage of parallel diodes.
See my schematic of the design below.