  Polymerization of RNA from a template DNA is carried out by a molecular
machine called RNA polymerase (RNAP). It also uses the template as a track on
which it moves as a motor utilizing chemical energy input. The time it spends
at each successive monomer of DNA is random; we derive the exact distribution
of these "dwell times" in our model. The inverse of the mean dwell time
satisfies a Michaelis-Menten-like equation and is also consistent with a
general formula derived earlier by Fisher and Kolomeisky for molecular motors
with unbranched mechano-chemical cycles. Often many RNAP motors move
simultaneously on the same track. Incorporating the steric interactions among
the RNAPs in our model, we also plot the three-dimensional phase diagram of our
model for RNAP traffic using an extremum current hypothesis.
