How do you make a lego train 2 levels?

Question

For example i have one train at the bottom and then a whole new train at the top which signifies the second level? Explain in detail if possible :) thanx

Answer 1

Stack Them

Answer 2

Normally, when modelers want to make a train on two levels, they employ switch that sends the train onto a "helix", or a circular ramp of many intermediate levels, like you see in parking garages.

For a lego train, you might have to modify it a bit.  Rather than each circle being right on top of the one below it, you might have to make a spiral, where the radius changes as you ascend (so as to allow for the extra height of a Lego train).