All high-Tc superconductors have a layered structure, but the importance of this remains unclear. Some of these layers have chains of atoms with a local symmetry, which facilitates quasi-one-dimensional effects. We describe numerical simulations which suggest that lattice nonlinearities allow the transport of strongly localized and robust packets of vibrational energy (discrete breathers) along these chains. The results support previous studies which correlated these particular structural properties with superconductivity in these cuprates. © 2001 Elsevier Science B.V.