Abstract: By the model with the fusion of quark-gluon strings on a transverse lattice the correlations between observables from separated rapidity intervals in high-energy hadronic interactions are considered. The asymptotes of the long-range rapidity correlation coefficients between the multiplicities (n–n) and between the event-mean transverse momentum and the multiplicity of charged particles (pt–n) in these observation windows at large string density were explicitly calculated with the additional condition fixing the total number of initial strings. It is shown that this condition, which imitates in our model the fixation of the collision centrality class, has a significant impact on the behavior of the n–n and pt–n correlation coefficients for both homogeneous and inhomogeneous distribution of strings in the transverse plane.