  We study the phase time for various quantum mechanical networks having
potential barriers in its arms to find the generic presence of Hartman effect.
In such systems it is possible to control the `super arrival' time in one of
the arms by changing parameters on another, spatially separated from it. This
is yet another quantum nonlocal effect. Negative time delays (time advancement)
and `ultra Hartman effect' with negative saturation times have been observed in
some parameter regimes.
