Connectors for use in large scale trains JST connectors JST connectors are pretty common, and are often used in the hobby. They lock together, carry reasonable current, and are relatively compact. All Electronics, www.allelectronics.com, they carry a lot of different connectors already wired. This is where you can find the JST connectors used by Aristo and USAT. https://en.wikipedia.org/wiki/JST_connector 2 pin JST SM connector, used by Aristo and USAT - All Electronics part number CON-240 3 pin JST SM style CON-340 4 pin JST SM style connector CON-440 6 Pin JST SM style connector CON-640 I found 8 pin JST SM on ebay: common Aristo Craft connectors These are used on some of the older locos on the motor blocks, like the Aristo FAs: CON-230P also known as JST RCY connectors Here is the matching socket: CON-230S Aristo 4 pin connector used on Prime mover blocks, 2.5mm pin spacing, Molex SPOX, series 5264, part number 0050-37-5**3 where the asterisks are the number of circuits. In this case the exact part number is 0050-37-5043. I found the pins are sold several ways and in several finishes, bulk from Digikey 0008-70-1040 (bulk) and 0008-70-1039 (each), thse handle 22-28 gauge wire The crimper The header for the pcb is series 5267 and 5268, the terminal series is 5263 Small 2 pin connector: SBC-1 Pins are spaced 2mm apart Small 2 pin connector SBC-2 Pins spaced 2.5 mm apart. CON-2410, Connector used by Jim Carter in some LGB conversions All Electronics also has the matching headers, the site will typically show you the part numbers when you look up a connector.