One thing I’ve learned in my short career as a locomotive builder is that I take my engines apart a lot. It won’t do to have soldered connections holding the boiler where the lights are to the chassis where the wheel rotation sensor is and to the motor. Fortunately, it seems like the 1mm headers from Sullins can stack. So, I’ve devised a cunning plan where the motor and chassis plug into the boiler, and the tender plugs onto the other side in a three-connector stack.
The pin-out diagram on that page is wrong, and here is the corrected version (for future Rene). Blue is neutral, white is headlight, green is classification lights.
Putting them all together was patience-testing, especially when it came to the huge 28 gauge motor wires. For those, I wound up making some 1×2 mm spade connectors so there would be sufficient pin left to mate with the female connector. I’m taking a little break from soldering really tiny connectors so I can build the tender chassis and measure the length of the wire between the tender and engine.