I road behind the 46 in '77. Was listening to the stack talk when it suddenly changed and very shortly after "CLANK-CLANK!" was heard traveling under the car. I told my wife, "That's not good!" We limped into the wooded grove stop, and as we were walking off the train, the crew was inspecting the engine. It had thrown a valve link, I didn't see any damage, so I suspect the connecting pins fell out. It seemed obvious to me to block the valve on center, prop open that cylinder's cocks and go back on three cylinders (not certain how they would lube that cylinder though), but they didn't want to hear anything from a 25 year old "kid." We continued on to Ukiah and the '46 and her train headed back to Fort Bragg. When our train got back to the grove, no meeting train! They had tried to go back to FB without doing anything and about half-way there that cylinder valve moved and they were stuck. Had to call another crew to come tow them in, and then bring a train up to pick us up. Took a few hours! The conductor on the diesel train told me the engine crew only ran the engine, didn't even oil around, a mechanic came and did all that. I wonder if that was the last trip on CW for 46? This was in early September of '77.