Building A Double Slip Switch With A Fast Tracks Assembly Fixture May 10, 2019 19:23 These instructions apply to all scales and sizes of Double Slips. Click here or on the image to download your copy now. Related articles Building Curved (and Straight) Turnouts With Fast Tracks TwistTies Building Double Crossovers With a Fast Tracks Assembly Fixture Building Crossings With A Fast Tracks Assembly Fixture Building Turnouts Using Fast Tracks Assembly Fixtures. Building A 3-Way Switch With A Fast Tracks Assembly Fixture