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| Re: Of brake stands and piping (467836) | |||
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Re: Of brake stands and piping |
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Posted by Hoghead on Sun Jul 29 04:14:20 2007, in response to Of brake stands and piping, posted by SelkirkTMO on Sat Jul 28 23:40:58 2007. I liked the 26L brake equipment. It worked very well. Many complaints I heard were not because of the brake equipment--they were actually caused by sloppy maintenance. For example: big whine from the hogger: "I can't take this train out--the automatic leaks down when the air is set." Well, when this happened, there was a pretty good chance the locomotive had a recent inspection. Air guages were tested, and when re-connected to the brake system, the connection at the equalizing gauge was not tight. The automatic brake handle controls the air in the equalizing portion--the rest of the equipment matches the brake pipe pressure to whatever the equalizing pressure is--if there is any leak at all in the equalizing portion, self-maintaining does not work. The good news is the feed valve is in a very handy position, so the smart hoggers had no problem braking their train using the feed valve. Definitely beats reaching to the floor or some other awkward position to adjust the feed valve as on some other types of brake equipment.The other most common complaint was probably the feed valve freezing up in very cold weather. That was caused by moist air. Locomotives used to have no air drying equipment whatsoever. Railroads would dump alcohol in the main reservoirs to help control the water in the air. Modern day locomotives have excellent moisture control equipment on the air systems. It could get pretty interesting trying to operate a mile long train when the temperature was 35 degrees below zero and the feed valve kept freezing up. You have the air set on a down grade. The feed valve freezes up. You give the brake stand a hard whack with a monkey wrench or the nearest heavy object. Feed valve breaks loose. Only problem is: the 3 or 4 pound increase in brake pipe pressure when the feed valve broke loose may be enough to release the brakes on your entire train. Whee. Away we go. Or, flying along at 60 MPH when the feed valve freezes up. Whacked it and got the air flowing again. Only problem, there was enough of a brake pipe reduction to cause some cars to set, but not enough of an increase for a clean release, so you have to do maybe a 10 pound set, then release, then hope the feed valve does not freeze up with the rush of cold, moist air charging the brake pipe. Of course, there is the dynamic brake (called the dramatic brake by a now deceased hoghead because "you were never quite sure what was going to happen when you used it")--and the newer locomotives have amazingly good dynamic brakes. However, after a run of a thousand miles through snow and blowing snow without using the air brakes, it can be quite interesting tring to hold the train on a hill--there is so much snow and ice on the brake shoes, they will no longer effectively brake. I recall an instance of a unit coal train that had a knuckle failure near the head end. The rear 100 cars or so of the coal train--brakes in emergency--took off and rolled several miles down hill. The train had been operated a long distance through lots of snow, using dynamic brakes only. |
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