Create Each Part
Train Body Video
Stack Video
Hitch Magnet
Hitch Peg
Wheel Video
Axle Peg
Linkage Arm Video
Linkage Peg Video
Cow Catcher Video
Straight Track Video (this is on Inventor but it gives you a good idea of how to do it)
Create a properly dimensioned technical drawing for each part
Train Body- Front, Top, Left Side, Right SIde
Stack- Front, Top, Bottom
Hitch Magnet- Front, Top
Hitch Peg- Front, Top
Wheel- Front, Section View (Lined Portion on Spec Sheet Drawing)
Axle Peg- Front, Top
Linkage Arm- Front
Linkage Peg- Front, Section View (Lined Portion on Spec Sheet Drawing)
Cow Catcher- Front, Back, Bottom, Section View (Lined Portion on Spec Sheet Drawing)
Track- Front, Top
Be sure to add bubbles
Constrain three pieces of track together (assemble)
Do a rendering of your train on the track
Add more details to train or create extra train cars if you finish all the above steps.