How Air Brakes on Trains Work - Article Example

How Air Brakes on Trains Work By ……….. ……………. Inside this Article Introduction 2) Basic understanding on the air brake system on a train. 3) The Main Parts of the Air Brake System and Functionalities Could you be amongst the many people who wonder what sought of miracles happen in order to stop a train? How can air, moving back and forth, bring a thousand-tons train into a manageable stop? A typical diagram indicating some detailed parts of the Air Brakes and where they are positioned. By Josh Briggs Supposedly, by reading this piece of work, you will have acquired a better understanding on this phenomenon; as it appears to some. Certainly, it won’t cost a lot if some basics are revisited. The air brake may be defined as the universal fail-safe, typical, train brake applied by railways globally. Despite the level of complexity, air brakes use the basic physical features of compressed air. Basic Understanding on the air brake system. A train in motion generates kinetic energy that has to be eliminated from the train system in order to stop such a moving train. Consequently, kinetic energy is converted into heat energy. The conversion process is often managed by fixing a contact material at the rotating discs (wheels), which is in turn fixed to the axles. Therefore, the fixed material causes friction thus producing heat out of the kinetic energy. Eventually, there is a slowdown of the wheels and the whole train stops. The braking material assumes the form of a pad or block. Most trains are installed with braking systems that feature compressed air like the power to force blocks on to pads or wheels on to discs. Such systems are referred to as "pneumatic brakes" or "air brakes". A “brake pipe” is used to transmit the compressed air into the system. Varying the level of air pressure results into a variance in the brake’s state of application in every locomotive. The train may apply the brake, hold (release) it after an incomplete application. A diagram showing the external view of the air brake on a train. By James The Main Parts of the Air Brake System and Functionalities Compressor The compressor serves as the pump necessary for drawing air from the atmosphere, while compressing it for further usage on the train. The principal function of the air is portrayed in the brake system, even if compressed air is also used in other means. The compressed air is stored in the Main Reservoir for braking purposes as well as for other pneumatic train systems. The driver’s brake valve acts as the means via which the train driver regulates the brake system. This valve has a minimum of such positions as: "Running", "Lap", "Release", "Emergency", and "Application". Additionally, a position to "Shut Down" is included to help lock the valve when it is not on use. Every position plays an autonomous role in the braking system. The "Release" position links the brake pipe to the main reservoir. This effort helps in raising the available air pressure within the shortest time possible in order to acquire an instant release when the driver is signaled to restart the train. The selection of the feed value is acquired when the valve is in the position, "Running". This facilitates the maintenance of a slow feed within the brake pipe in order to counteract the losses or small leaks in the connections, brake pipe and connections. The role of the "Lap" is to help close the link between the brake pipe and main reservoir, as well as to hinder the atmospheric connection when a brake application is committed. The Lap has an absolute role of providing a partial brake application. The Lap, thus, serves a role of partial release, which cannot be achieved with the usual types of air brakes; specifically the air brakes featured on the United States freight trains. The "Application" position hinders the links from the principal (main) reservoir as it exposes the brake pipe unto the immediate atmosphere. The air pressure in the brake pipe reduces while the air escapes. Most braking systems have their valves provided with an additional position for "Emergency". While the Emergency position operates similarly to the Application position, the “Emergency” position has a larger opening to atmosphere thus providing a quicker brake application. Triple Valve On each vehicle, the brake operation is regulated by a three-functioned subsystem, the "triple valve". The three functions of the triple valve include – releasing the break, applying it, as well as holding it; maintaining the current application level. A Triple valve and the auxiliary reservoir. By Piers Connor A slide valve is installed in the triple valve to help in detecting variances regarding the pressure within the brake pipe. Consequently, the slide valve reorganizes the existing connections accordingly; within the triple valve. The slide valve responds with one of the three feedbacks, recharging the auxiliary reservoir while opening the exhaust of the brake. The other response would be by closing the exhaust brake cylinder thus allowing air feeding of the air auxiliary reservoir into the cylinder. Lastly, the slide valve can hold the air pressures within the brake cylinder and auxiliary reservoir at the current application level. Brake Pipe The brake pipe runs the train’s length that transmits changes in pressure necessary for controlling the brake on all locomotives. Brake pipe is linked between locomotives by adjustable hoses, which can easily be separated to allow locomotives to be delinked independently. The application of the air pressure system ensures the brake "fail safe;" air loss within the brake pipe causes the application of brake. The loss of pressure in the brake pipe may be as a result of many reasons. The first reason would be due to the regulated pressure reduction by the driver. The driver can also evoke an instant pressure reduction through the use of the emergency application position on the brake valve. Additionally, the conductor can cause an instant pressure reduction through the emergency valve located at the guard’s (conductor’s) position. Passengers can also cause a rapid pressure reduction as observed on several railways; they can use an emergency subsystem to access a valve. A burst hose or pipe can as well cause a rapid pressure reduction. Lastly, a rapid pressure reduction can be caused by the parting of hoses when the train become derailed or parted. Feed Valve In order to ensure that only the air pressure of the required level is maintained within the brake pipe, a feed valve fixed between the brake pipe and main reservoir while the driver selects the "Running" position. A diagram showing a piston and brake pads. By Josh Briggs The feed valve is fixed to apply at defined operating pressure. Although various railways use varying pressures, they all range from 4.5 to 6.2; bar (65 to 90 psi). Equalizing Reservoir The equalizing reservoir, a small-sized pilot reservoir that serves to enable the driver choose the appropriate pressure within the brake pipe while executing an application. When the driver makes an application, shifting the handle of the brake to the position of application does not imply a direct discharge of the brake. However, such a function allows air to proceed from the equalizing reservoir. A relay valve is linked to the equalizing reservoir; the relay valve is referred to as the "equalizing discharge valve". Technically, the equalizing reservoir helps in overcoming the challenges which may arise within a brake pipe that is too long. A long brake pipe will imply that small pressure variances in pressure as chosen by the train driver to acquire a low braking rate would not be reflected on the driver’s gauge until the exerted variance in pressure stabilizes in every locomotive. The equalizing reservoir as well as associated relay valve lets the driver select a pipe pressure break, even when the actual pressure has not yet stabilized. Brake Rigging The brake system is another train braking subsystem through which the brake cylinder’s piston moves to transmit pressure to the pads (brake blocks) fixed on each disc. Usually, brake rigging can be complex, commonly installed on a passenger car; implies that there has to be two blocks fixed to every wheel, resulting to a total number of sixteen wheels. A diagram indicating brake cylinder and the break pipe. Brake Rigging calls for a cautious adjustment in order to ensure that every block operated from a given cylinder provides an application rate that is even to every wheel. Changing a single block implies that every block on that axle must be checked and adjusted. How Air Brakes on Trains Work By ……………… Inside this Article 1) Introduction 2) Basic understanding on the air brake system on a train 3) The Main Parts of the Air Brake System and Functionalities More Information on How Air Brakes Trains Work Ogden Brothers Trains How Air Brakes Work RailRoad.net Work Cited: “AIR BRAKES”. Accessed April. 2012. http://www.railway-technical.com/air-brakes.shtml Briggs Josh. “How Air Brakes Work”. Accessed 23 April. 2012. http://auto.howstuffworks.com/auto-parts/brakes/brake-types/air-brake2.htm Connor, R Piers. “Air Brakes”. Railway.net. Accessed 23 April. 2012. http://www.railroad.net/articles/railfanning/airbrakes/index.php Krug, Al. “NORTH AMERICAN FREIGHT TRAIN BRAKERS”. Accessed April. 2012. http://www.railway-technical.com/brake2.shtml “Prototype Railroading. How Air Brakes Work”. Accessed 23 April. 2012. http://ogdenbrotherstrains.blogspot.com/2011/09/prototype-railroading-how-air-brakes.html Stringer, William. “How do air brakes on a train work?” Accessed 23 April. 2012. http://www.helium.com/items/2245394-how-do-air-brakes-on-a-train-work Read More