In this paper, failures of valves in cylinder head of diesel locomotive are contemplate and analyzed. The design of the diesel engine has persistent to procure over the years. Many of the things ware alternated in response to the customer’s increasing horsepower demands. There are many things are there which make a valve fail. The usual causes are thermal and mechanical overstresses, longitudinal cyclic stress, and creep conditions, forging defects etc. these leads to copious troubles in performance of Engine. The valve troubles embrace valve breakage, valve face wear, Steam and guide wear, necking of valve stem and other valve problems. Further because of pressure, the density of exhaust gases is also comparatively high and if the valves do not receive adequate cooling, they can overheat, burn and fail. The changes in microstructure, Compositition and material properties of valve were studied and analyzed with help of many tests. The specimens were prepared out of failed engine valve whereas new valves were also analyzed for sake of comparison. Anything that interferes with valve cooling or creates extra heat in the valve can lead to premature valve failure and another is escape of flue gases from Cylinder head which causes decrease in Efficiency of engine. In order to investigate the effect of failure modes on damaged valves, a failed valve taken from a plant was examined. This paper describes a detailed metallurgical investigation and fractographic analysis on that particular exhaust valve of a diesel locomotive engine, which catastrophically failed in service.