  Using our extensive radio, optical, near-IR and X-ray imaging and
spectroscopy, we consider the reason for the unusually large number of radio
detected galaxies, mostly found outside the cluster core, in Abell 2125
(z=0.2465, richness class 4). With 20-cm VLA data, we detect continuum emission
from 90 cluster members. The multiwavelength properties of these galaxies
suggest that most of the radio emission is due to an enhanced star-formation
rate. The dynamical study of Miller et al (2004) suggests that Abell 2125 is
undergoing a major cluster-cluster merger, with our view within 30 degrees of
the merger axis and within 0.2 Gyr of core passage. The combination of
projection effects and the physical processes at work during this special time
in the cluster's evolution seem likely to be responsible for the unusual level
of activity we see in the cluster. We argue that tidal effects on individual
cluster members, often far from the cluster core, are responsible for the
increased star formation. Our results are consistent with the idea that disk
galaxies during this phase of a cluster's evolution undergo rapid evolution,
through a burst of star formation, on their way to becoming S0's.
