A unified quantitative model of the formation of positronium, muonium and radiolytic hydrogen is proposed. It includes a description of the slowing down and thermalization stages, which are responsible for the initial spatial distribution of primary intratrack species. Possible reactions of hot electrons and positrons are discussed. Formation of Ps (Mu) and radiolytic hydrogen is described in terms of diffusion-recombination reactions between thermalized, but yet not solvated positron (muon), radical-cations and track electrons. It is suggested that this intratrack quasi-free electron released from a molecule by the primary ionizing particle is a common precursor of all radiolytic products.