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If you’re reading this blog, you’re familiar with air brakes on American railroad trains. I’m not saying you know exactly how they work, but you know of them, and of the familiar hisses of compressed air escaping from locomotives or trains. Some of these hisses are quite loud, but others may be short bursts of air as valves lift to maintain the correct pressures for braking and for other air-operated appliances on American trains.
Air brakes have been around since before any of us were alive, unless you are now over 117 years old. The federal government mandated the Westinghouse air brake system to be used on all railroad trains by 1900.
Virtually all railroad air brakes in use today are based on this system. Simply stated, the system uses a system of reservoirs and valves on each car, and a train pipe that runs the length of the train that carries the air signal from the locomotive or control stand if located in other than a locomotive. The pipe also charges the reservoirs. The virtue of the system is that air pressure is used to hold the brakes off. Any drop in the pressure in the air pipe signals the system to apply brakes. Hence, any failure in getting air pressure to the train, including a separation of the train, will cause the brakes to be applied. For obvious reasons, the Westinghouse system is much safer in terms of emergency stopping, particularly in long trains, than a straight air system where the application of brakes depends on how fast the air can be pumped to the cars.
A drawback of the Westinghouse system is that changes in air pressure take time to propagate through the train pipe. The last car on a long train will brake last—not always desirable given the amount of slack in even the tightest of coupling systems. Some of this problem has been mitigated in recent years with the advent of mid-train and end-of-train locomotives operated by radio signals from the control. Such locomotives can be made to reduce brake line pressure on signal from the control stand, thereby starting a brake application signal propagating from their locations in the train.
Electronically Controlled Pneumatic (ECP) braking, uses a similar system to maintain air pressure in reservoirs on all cars. However, the signal to a valve to reduce pressure and apply the brakes is transmitted through a control wire and is therefore virtually instantaneous on all cars.
Simple? Perhaps. Both systems are quite simple when you come down to it. That’s why it’s hard to put your finger on the benefits to be had from converting all rolling stock to ECP. A benefit touted for the railroads is the ability to carry heavier loads at higher speed without exceeding the limitations of safety. It has also reported that fuel savings as high as 10% can be had as a result of two factors: First, ECP brakes allow smoother train handling and therefore less need to manipulate engine RPMs, and, second, the air compressor has to work less because brake line pressure doesn’t have to be recharged after each brake application.
So why has the U.S. Department of Transportation withdrawn its ECP brake rule? The rule, promulgated when it appeared that train loads of crude oil tanks and ethanol tanks would only increase over time, and in the wake of a spate of fiery accidents involving crude by rail, called for a two-phase compliance of ECP on all tank cars carrying hazardous materials starting in 2021. In 2015, Congress, as it is wont to do, threw a wrench in the works by requiring that the Government Accountability Office and the National Academy of Science study the effectiveness and cost effectiveness of implementation of ECP before the DOT could implement.
That study came out this past October, and, lo and behold, just as your intuition told you that there wasn’t much difference between Westinghouse-based air brakes and ECP, the NAS was “unable to conclusively state how well ECP brakes perform in an emergency as compared to other braking systems.” (as quoted at www.lexology.com) Furthermore, the cost of implementation was found to be three times higher than the benefits mentioned above.
Two footnotes: The political left has gone on the record against the dropping of this rule. The knee-jerk reaction is that dropping the rule is another action taken by a regulatory agency now controlled by President Trump to sacrifice safety for the bottom line of the nasty railroad corporations. Nothing is further from the truth, if you believe that the GAO and NAS are both able to do unbiased analysis, which they are. In fact, the rule was itself a subtle way for the Obama administration to slow down the development of crude oil production and had nothing to do with actual proven safety measures.
Oh, and, second footnote, having ECP on a train does nothing to prevent speeding. Without Automatic Train Stop or Positive Train Control, the operator still has to apply the brakes to reduce speed.
No wonder the railroads opposed the rule. So, thus ends another chapter in the saga of the Regulatory State. I just wonder how much the Congressional studies cost.
©2017 – C. A. Turek – mistertrains@gmail.com
(Charles A. Turek is a writer and novelist based in Albuquerque, NM. After four decades working in areas of the insurance industry related to transportation, he now writes on all aspects of American railroading. Charles is a political conservative but believes in public funding of passenger rail as a part of the federal government’s constitutionally conservative obligation to provide for defense and public infrastructure so that private enterprise may flourish.)
