A compact modular assembly of a geared power train (100) and generator (400) suitable for use in a wind turbine application to maximize a step-up ratio between an input and output within a limited radial space. The power train is configured as a hybricyclic split-compound planetary gearing system with a grounded closed carrier flex pin system in a high torque stage (A), and an open carrier flex pin system in a low torque stage (B), having a step up ratio of approximately 30:1. To facilitate modular assembly and disassembly of the power train and generator, each component is mounted independently to opposite sides of a common support structure (500) anchored to a bedplate (502).