I want to electrically connect my N scale lighted passenger cars together. The goal is to reduce flickering by having 32 wheel pickup instead of just 8. I'm looking for a small, non keyed connector. I'm planning on marking the bottom so that the pin on the left goes to the left side of the car. That way it doesn't matter which way the car faces. Any recommendations?
Digi-Key or Mouser is where I usually start looking for electronic components. Tony's Trains sells micro connectors too.
You can do much better (smaller) than header pins. Do a search for Molex Picoblade and/or JST GH. The Picoblade series and the GH series are both 1.25mm pin-to-pin center - that's half the 2.54mm for standard header pins. Molex and JST are two entirely separate companies that each produce commonly used connectors. Their connectors are frequently confused with each other as they do look very similar upon casual inspection. Note, however, they don't mate with each other. Pick one and stick with it. And be careful what you read online as JST connectors are sometimes referred to as 'Molex' and vice versa.
I was going to recommend Harwin Gecko series connectors, but their smallest is 3x2 contacts on 1.25 mm pitch. The Molex Picoblade that lyncher mentioned is available in a 2-pin wire-wire configuration. Same 1.25 mm contact pitch, polarized*, 2.5A current capacity per circuit. However, durability is limited to only 30 mate/de-mate cycle (contacts are only flash plated gold,) so this could be an issue for your application. Thicker contact plating may be available to survive more mating cycles, but probably at a price and minimum qty beyond your budget. I only found JST GH in wire-board connections, not wire-wire. *Non-polarized connectors are just begging to be mis-mated, with destructive results in this application (unless your track power system has less than 2.5A capacity).