  The present study deals with LRS Bianchi type I cosmological model
representing massive string. The energy-momentum tensor for such string as
formulated by Letelier (1983) is used to construct massive string cosmological
models for which we assume that the shear scalar ($\sigma$) is proportional to
the expansion scalar ($\theta$). The study reveals that massive strings
dominate the early Universe. The strings eventually disappear from the Universe
for sufficiently large time, which is in agreement with the current
astronomical observations. Some physical and geometrical behaviour of models
are also discussed.
