This is a new K'nex Roller Coaster propulsion system that uses 2 wheels instead of using a chain. Very practicle. These steps will show you how to build the main part, then you add it to your roller coaster. It uses 2 motor. For me I have one that always run- on motors(left) and one that is remote (right) but you can put 2 run-on motor also.
Step 1: The Support Base
Make this! This is the base that support the tracks. You may not have to build that if you just want to add it to your roller coaster.
Step 2: The Tracks
This is how the tracks need to be made, but you can modify it to fit on your roller coaster.
Step 3: The Motor Assembly #1
This step is to make the frame of the two motor assembly. You need to make four of them.
Step 4: The Motor Assembly #2
Here you add the motors, wheels, rods and spacers to build the propulsion module. LOOK CAREFULLY
Step 5: Assembly #1
In this assembly, you have to connect the motors to the tracks.
Step 6: The Final Assembly
Now install the track on the base support, add elastics to pull the motors upwards, install the tubing on the tracks, and you're ready to go.
If the wheel don't grip the wagon adjust the elastics to be tighter.