  We develop some techniques to study the adiabatic limiting behaviour of
Calabi-Yau metrics on the total space of a fibration, and obtain strong control
near the singular fibres by imposing restrictions on the singularity types. We
prove a uniform lower bound on the metric up to the singular fibre, under
fairly general hypotheses. Assuming a result in pluripotential theory, we prove
a uniform fibre diameter bound for a Lefschetz K3 fibred Calabi-Yau 3-fold,
which reduces the study of the collapsing metric to a locally non-collapsed
situation, and we identify the Gromov-Hausdorff limit of the rescaled
neighbourhood of the singular fibre.
