2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/35716Beginning with a special form of the Einstein-Rosen metric, we find new cosmological solutions of the Einstein equations, having two hypersurface-orthogonal Killing vectors , with ideal fluid. The equation of state is in the most cases of the form $p = γρ$.13 pages, latex, no figures, rmansouri@aip.deGeneral Relativity and Quantum Cosmologytext