 Accepting orders from a myriad of manufacturers also led to BR acquiring an unnecessarily diverse locomotive fleet, with large numbers of different but similar classes.This increased the cost and complexity of maintenance and led to operational difficulties (for instance there was no universal system for multiple working).The poor reliability of many of the locomotive designs procured under the Modernisation Plan led to much lower availability ratings than predicted and the large-scale withdrawal of several classes or the curtailing of planned orders, leaving BR short of suitable motive power in some areas.