A couple of things that would make the simulator even more useful:
Blue links on the chains so we can see the speed not just on the parts
Ability to add text to the parts, eg R1 or R2 to tell different resistors apart
There are other things that would go a little out of the scope of direct physical implementation:
Measure the tension and speed of a chain directly, without having to go through adding appropiate voltmeters and/or ammeters. (You could think of this as feeling the chain as it moves.)
A more quantified output from the ammeters.