  We analyze light and velocity curves of the eclipsing blue straggler V60 in
the field of the globular cluster M55. We derive Mp=1.259+-0.025 Msun,
Rp=1.102+-0.021 Rsun, Mbol,p=3.03+-0.09 mag for the primary and Ms=0.327+-0.017
Msun, Rs=1.480+-0.011 Rsun, Mbol,s=4.18+-0.12 mag for the secondary. We derive
an apparent distance modulus (m-M)V=14.04_-0.09 mag. Based on the systemic
velocity, distance, and proper motion of V60 we conclude that the system is a
member of the cluster and argue that its present state is a result of rapid but
conservative mass exchange which the binary is still undergoing. We report a
peculiar blue excess on the ascending branch of the primary eclipse of V60 and
discuss its possible origin.
