Because of their age I figured that coaches from the early 1900s wouldn't be lit up nearly as bright as the 1950s series passenger cars so I went with much dimmer LEDs. I ended up using very low current on four of the wide angle LEDs in each coach. The light is very dim, just enough to tell that there are passengers inside the cars. Each LED draws 96 micro amps from a 3.7 volt LIR2032 rechargeable Lithium Coin Cell through a 15KΩ ¼ watt resistor. Static charge on the Coin Cell is 4.13 volts new and 4.08 volts after a few discharge cycles.
I used a 4 pin DIP IC full wave 1 amp rectifier as a float charger with a 470Ω ¼ watt resistor to limit the Coin Cell charge current to 20ma (40 ma is max charge for a LIR2032 Coin Cell) with 14 volts from the rails (DCC). My normal DC working voltage using my old time wood burning 4-6-0 locomotive that tows my old timer cars is about 8 volts and the charge to the Coin Cells is in the vicinity of 5ma at 8 volts. With a total load of the four LEDs at under 400 micro amps the Coin Cells are still floating at 4.08 volts.
The picture above is the car floor with a 2 pin micro connector installed to supply track voltage to the rectifier. I use the micro connectors for everything, they are slick for there size and will carry 2 amps.
This shows the connector "tower" mounted to the window section to pass the power from the floor connector to the car shell.
This shows the inside of the shell, the four LEDs, Coin Cell & holder and the micro connector.
This is the inside of the roof or attic of the car. You can see the wiring including the Latching Reed Switch that turns the LEDs on and off.
This project turned out exceptionally nice, the Coin Cells work great and will power the car for several hours without track power.
The Old Time Coaches came with plastic wheel trucks and Talgo couplers so I replaced the trucks with Kadee metal frame trucks and metal wheels for power pickup.
With the loss of the Talgo couplers I added Kadee Draft Gear to the car frame. I will install Kadee #119 SE couplers as I use them on all of my passenger cars.
I added LED powered Cal-Scale Marker lights to the baggage end of the Combine. When I was researching old time train rear markers I found a picture of this configuration so I did it to it. My 4-6-0 will tow two 44 seat Coaches with the Combine markers lighting up the rear.