The intermediate disorder regime is a scaling limit for disordered systems where the temperature is scaled with the size of the system. For a random polymer given by a single random walk, Alberts, Khanin and Quastel proved that under intermediate disorder scaling the polymer partition function converges to the solution to the stochastic heat equation. In this talk, I consider polymers made up of multiple non-intersecting walkers and consider the same type of limit. The limiting object now is the multi-layer extension of the stochastic heat equation introduced by O’Connell and Warren. This result proves a conjecture about the KPZ line ensemble, which I will also introduce. Part of this talk is based on joint work with Ivan Corwin.