Abstract :
IN THE EARLY STAGES of the development of railway traction equipment the need for some form of ventilation became evident. This need increased with the continuing demand for increased output. As a result, cooling systems evolved from self- to forced ventilation. Their development was not, however, an unmixed benefit. Any ventilation tends to draw dirt, snow, moisture, and other contaminants into the machine, with harmful results. The undesirable effects may be reduced by design measures aimed at the following: 1. making the components more resistant to damage, 2. preventing the accumulation of foreign matter in critical locations, and 3. cleaning the air before it enters the machines The proper measures to employ in a given instance are determined by design, practical and economic consideration.