Аннотация:A problem from thermodynamic formalism for countable symbolic Markov chains is considered. It concerns asymptotic behavior of the equilibrium measures corresponding to increasing sequences of finite sub-matrices of an infinite nonnegative matrix $A$ when these sequences converge to $A$. After reviewing the results obtained up to now, a solution of the problem is given for a new matrix class, which differs from those studied previously in some essential feature. A geometric language of loaded graphs instead of the matrix language is used.