Thanks Gap.......great response from all around.....more to learn, learn, learn !!! Strictly amateur but can follow in general.......take it Rx is resistor, don't know Servo....I thought reversing motor would cover polarity......I have 2 x 3mm leds at each end ...assume in series.....do they need resistors?
From your plan the lower led is a separate lead connected to rear carriage.........Regards, Mardy
OK Sorry for the confusion the terminology I use is;
Batt = battery
ESC = Electronic Speed Controller
RX = Receiver
TX = transmitter (not shown)
DPDT = Double Pole Double Throw switch
Servo = a servo used to throw the switch
Mot = Motor
To calculate the limiting resistors I just google a "LED Resistor Calculator" put in the voltage, used 20mA as a default current, or whatever current spec the LED has, and a diode voltage drop of 0.6V it does the rest.
This is a link to one which will actually give you a schematic or a wiring diagram.
http://led.linear1.org/led.wiz
I use only one resistor and wire the LEDs in parallel just reverse physically i.e. cathode to anode and vice versa. As diodes only conduct one way depending on the polarity of the voltage only 1 will light.
For 2 LEDs in each headlight I wire them in series and treat them after that as one LED.
You can put the LED anywhere in the train via a lead so long as it is electrically connected to the other LED and the motor input.
Some of my locos only have the motor in them with all the other R/C gear and batteries in a tender, I run 2 wires to the loco for motor and wire the front LED across the motor input, the rear LED on the tender is wired across the reversing switch output which electrically is the same point as the motor input.
My LEDs only light once the train starts to move but some people wire them so that they are on permanently and depending on the direction which one is on.
Hopefully that is clear as mud for you
Any other questions just ask either in here or via a conversation.
