Document wO6joewevKBvgMOOr9L2V0vJ

(m) The Johns-Manville #600 folded and compressed lining has been standard on our brakes since 1930* It was selected after careful tests which showed that it had a minimum coefficient of friction of .30 and good lining life. Most of our competitors used molded , linings and claimed that their lining v;as superior to that used on C-H brakes. However our tests on their molded linings indicated that the J-M #600 lining was superior. As a matter of fact, we learned that most brake manufacturers did not conduct lining tests but simply accepted the lining manufacturers data. Some of the brake manufacturers Increased the thickness of the. molded lining and told customers that their lining life was greater than the life of our ' lining by the ratio of thicknesses. Our tests dis proved this point and Indicated that the heavier : lining was used in order to approach the life of thinner #600 linings used on our brakes. Some steel mills carried #600 linings in several thlck- ' nesses so that they could replace molded linings with the #600 material. There have been improvements in molded linings, but I recommend that when going to the bonded linings we do not change from the folded and compressed lining to the molded type unless our tests show that the new molded lining is truly superior. The folded and compressed lining has been an important feature of C-H brakes for many years. A change to a molded lining shouldn't be made lightly. Added 9-13-67 - l8a SCF-EC-1039 SC-EEI-0835 0