  The purpose of this paper is to study rank metric codes over Galois rings. In
particular, we prove MacWilliams identities for finite chain rings relating the
sequences of $q$-binomial moments of a code and its dual and for Gabidulin
analogues of free codes over Galois rings we prove the corresponding
MacWilliams identity as a functional expression relating the weight enumerator
of the dual with the MacWilliams transform of the weight enumerator of the
original code plus one extra term attached to the zero divisors.
