  The Faddeev-Yakubowski equations have been solved in configuration space for
the four nucleons system. Results for bound and scattering states in the
isospin and S-wave approximation for different (T,S) channels are presented.
The n-t elastic cross section has been also calculated with realistic
interactions. A special interest was devoted to the description of the observed
resonant structure at $T_{lab}\approx 3$ MeV which is well reproduced only by
the simple MT I-III potential.
