By proper choice of operating conditions, an oxygen absorption test can be used to predict the oxidation stability of railroad oils in high severity diesel engines. This paper describes a modified oxygen absorption apparatus and the conditions chosen for testing railroad oils, and discusses the effects of soluble metal catalysts, the correlation between volume of O2 absorbed and various properties of used railroad oils, and correlation with engine tests. This test is also used to determine the effects of railroad oil additives and base oils on the oxidation stability of the lubricant. It involves circulation of oxygen through the oil at a controlled temperature and flow rate, in the presence of soluble metal catalysts, until a definite quantity of O2 has been consumed. The rate of O2 consumption is constantly monitored by a transducer. The equipment is semi-automatic in that it plots an O2 absorption curve automatically and shuts itself off when a preset quantity of O2 has been consumed.