2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/2114We do not fully understand the dynamics and evolution of a radio galaxy. Models of classical double (Type II) sources are in a reasonable state, but these objects are rare. Non-type II sources (generically called Type I) are far more common, but much less well understood. In this paper I use the data to suggest possible new models for Type I sources, and discuss the physical questions which these new models raise.8 pages, 2 figures, to appear in Particles and Fields in Radio Galaxies, ASP Conf. Series, eds. R. Laing and K. BlundellAstrophysicstext