Model 402 4-Track Zellner Yard - PDF Drawings

2. Other Comments About The Drawings When To Use The 1651 & 1653 Templates (instead of using these Model 402 drawings) If you already have a 2-track unit built per the Model 1651 design, then you can add the #1653 Helper Control Unit to expand from 2 tracks to 4 tracks, as described in Section D1, 4 Track Expansion. Too Many Drawings ?? People sometimes complain that my drawing sets have too many drawings, and they are too confusing. The template drawing is the 'key' drawing. You could just use this drawing, and IGNORE the others. The other drawings are reference drawings - photos, track layout, schematics, initial conditions for operating, parts lists, building dimensions, signal layout. Drawing Confusion ?? These drawings can be somewhat confusing, as they have evolved from one design to another design, and their usage overlaps from one unit to another unit. Assuming you are in the continental United States, the easiest way may be for you to call me on the telephone using the contact link at bottom (or email me a US phone number), and I can call you and give you my opinions, based on what you want to construct.