CHAPTER XIII.

ACCIDENTS TO THE VALVE-MOTION 143

Running Worn-out Engines.--Care and Energy defy Defeat.-- Watching the Exhaust.--The Attentive Ear detects Deterioration of Valves.--Locating the Four Exhaust Sounds.--Identifying Defects by Sound of the Steam.-- Accidents Prevented by attending to the Note of Warning from the Exhaust.--Neglecting a Warning.--How an Eccentric-strap Punched a Hole in a Fire-box.--Interest in the Valve-motion among Engineers.--Trouble with the Valve-motion.--A Wrong Conclusion.--Locating Defects of the Valve-motion.--Position of Eccentrics.--Method of Setting Slipped Eccentrics.--Slipped Eccentric-rods.-- Detecting the Cause of a Lame Exhaust.--What to do when Eccentrics, Straps, or Rods Break.--Different Ways of securing the Cross-head.--Broken Tumbling-shaft.-- Broken Valve-stem, or Valve-yoke.--When a Rocker-shaft or Lower Rocker-arm Breaks.--Miscellaneous Accidents to Valve-motion.--Broken Steam-chest Cover.--Steam-pipe Bursted.--Testing the Valves.