SC-1 1 Empty/Load Equipment - PDF Free Download

Operation of the SC-1 The SC-1 empty/load equipment includes the use of an: S-1 Sensor Valve P-1 Proportional Valve Equalizing Reservoir

Piping Arrangements The brake cylinder pipe from the control valve is connected to the P-1 Proportional Valve. The pipe from the Proportional Valve directs air to the brake cylinder and sensor valve. SC-1 Empty/Load Brake Arrangement AB Type Control Valve A pipe from the sensor valve is connected to the Equalizing Reservoir. Equalizing Reservoir P-1 Proportional Valve From the Equalizing Reservoir there is a pipe connection back to the Proportional Valve. S-1 Sensor Valve Truck Side Frame Brake Cylinder Combined Aux. & Emergency Reservoir

S-1 Sensor It is secured to the car body bolster at a point where the sensor arm contact ball will touch the truck side frame on a brake application. The contact ball of the sensor arm will extend on each brake application to contact the truck side frame and provide an accurate loaded or empty brake application. The distance the sensor arm travels is controlled by the car weight compressing the truck springs. The sensor arm contact ball must be set properly to maintain accurate brake cylinder pressure for each brake application. There is no partial load or partial empty braking available. A loaded brake application occurs when there is approximately 20% loaded weight in the car. CONTACT BALL SENSOR ARM

P-1 Proportional Valve Air pressure from the control valve must go through the Proportional Valve before it is directed to the brake cylinder. The Proportional Valve provides a balance of brake cylinder pressure and equalizing reservoir for an empty brake application. A 50% or 60% Proportional Valve may be used based on the car empty weight versus the car loaded weight. The 50% and 60% Proportional Valves are not interchangeable. The 50% Proportional Valve is designed to provides 50% of the brake cylinder pressure to the brake cylinder for a full service brake application on an empty car. The 60% Proportional Valve is designed to provide 60% of the brake cylinder pressure to the brake cylinder for a full service brake application on an empty car.

Equalizing Volume This is a small reservoir in line from the Sensor Valve to the Proportional Valve. It will provide an air pressure balance with the brake cylinder on an empty car brake application. The amount of air pressure in the Equalizing Reservoir depends upon the type of Proportional Valve on the car, 50% or 60%. With the SC-1 Brake Arrangement functioning properly and the sensor valve set correctly, there is air in Equalizing Reservoir only on an empty brake application.

Operation Empty Car Service Brake Application 1 Air pressure from the auxiliary reservoir is directed by the control valve to the P-1 Proportional Valve. 2 In the proportional valve, the air is allowed to flow to the brake cylinder and sensor valve. Brake Application - Empty Condition AB Type Control Valve 3 Air in the sensor valve forces the sensor arm down. As the car is empty there is no weight to compress the car truck springs. As a result the sensor arm will move all the way down. 4 This opens a passage within the sensor valve to allow air to flow to the equalizing reservoir. Equalizing Reservoir P-1 Proportional Valve 5 Air in the equalizing reservoir will also flow back to the top side of the proportional valve s internal valve assembly. Truck Side Frame S-1 Sensor Valve Brake Cylinder Combined Aux. & Emergency Reservoir 6 This return air from the equalizing reservoir will cause the proportional valve to provide the correct balance of air in the brake cylinder and equalizing volume.

Operation Loaded Car Service Brake Application 1 Air pressure from the auxiliary reservoir is directed by the control valve to the P-1 Proportional Valve. 2 The proportional valve will allow the air to flow to the brake cylinder and sensor valve. Brake Application - Loaded Condition AB Type Control Valve 3 With a loaded car the truck springs are compressed making the car body closer to the truck side frame. The sensor arm s travel is now restricted. Equalizing Reservoir P-1 Proportional Valve 4 With limited travel the sensor will not allow air to flow to anywhere but the brake cylinder. Truck Side Frame S-1 Sensor Valve Brake Cylinder Combined Aux. & Emergency Reservoir 5 This provides 100% of the brake cylinder air pressure to the brake cylinder.

Operation Brake Release/Empty Car Brake Release - Empty 1 Air from the brake cylinder is directed back through the proportional valve to the control valve. 2 With no brake cylinder air at the sensor valve. The sensor valve arm will move up to the release position. Brake Release - Empty Condition AB Type Control Valve 3 The air in the equalizing reservoir is restricted from flowing back to the control valve. Equalizing Reservoir Equalizing Reservoir P-1 Proportional Valve Retainer Valve 4 The air from the equalizing reservoir is allowed to vent out the exhaust port on the bottom of the sensor valve. S-1 Sensor Valve 5 The sensor arm must move up to the release position thus allowing the air in the equalizing reservoir to escape. This ensures the correct brake cylinder pressure for each successive brake application. Truck Side Frame Brake Cylinder Combined Aux. & Emergency Reservoir

SC-1U Empty/Load Equipment The SC-1U (Unitized) Empty/Load equipment is designed for intermodal articulated cars. The SC-1U assembly is mounted on the truck assembly to ensure correct brake cylinder pressure is directed to that truck brake cylinder according to the load the truck is carrying. The S-1 Sensor Valve and P-1 Proportional Valve are mounted on a pipe bracket which also incorporates the Equalizing Volume. There are only two pipe connections to be made; IN from the Control Valve and OUT to the brake cylinder. With the S-1 mounted on the pipe bracket, the whole assembly must be mounted adjacent to the truck bolster to allow the sensor valve to measure the spring deflection. Flexible hoses are generally used to allow for truck swing and travel. There are four distinct models of the SC-1U. Each unit has its own piece number, available in right hand and left hand versions, with two different mounting arrangements. The P-1 and S-1 portions used on the SC-1U equipment are standard components. The pipe bracket determines the different piece numbers.

SC-1C Empty/Load Equipment The SC-1C equipment has the Sensor Valve and Proportioning Valve sharing a common casting. The required volume is contained within the pipe bracket portion, which may be increased by the addition of extra volume. As with the SC-1U equipment, only two pipe connections are required. The SC-1C Sensor/Proportional Valve is an Integrated Load Sensor Valve, Proportional Valve and Equalizing Volume. The Sensor/Proportional Valve consists of an operating portion which is mounted to a pipe bracket. The Pipe Bracket Portion also acts as the equalizing volume. This arrangement permits the easy removal of the operating portion without disturbing the car piping. The SC-1C is designed for use in specific equipment arrangements where the air pressure does not exceed 110 psig.

S-1 Sensor Adjustment Sensor valve adjustment may be necessary when: 1 The sensor valve is changed in accordance with AAR Rule 4 of the Field Manual of Interchange Rules. See AAR Rule 3, Chart A. 2 The sensor is not providing a correct brake cylinder pressure as noted on the brake cylinder measurement gauge. Pressure must be at least 20 psi lower for an empty brake application versus the loaded full service brake application. (AAR S-486-02) Securement Screws Plug 3 On the brake application of a loaded car, there is air directed to the equalizing reservoir. This will indicate the freight car is braking as an empty car. This is determined by low pressure in the brake cylinder as noted on the brake cylinder measurement gauge during the brake application or an exhaust of air from the sensor valve exhaust on a release of the brakes. * Components of the S-1 Sensor Valve and the set up of the valve for adjustment purposes are depicted to the right. Contact Ball Sensor Arm Adjusting Block Truck Side Frame

Tools & Equipment Requirements for Adjusting Car must be on a level section of track. The freight car must be secured against movement. AAR Approved Single Car Test Device must be used for testing and adjustment. Car must be empty. Block used for verifying loaded condition is 2 ¼ Adjusting block thickness to be equal to 1 / 5 the spring deflection between light and loaded car. Where spring deflection is unknown use a 7 / 16 block. We recommend that if new center plate lubricator pads are installed, 1 / 8 maximum be added to the adjusting block thickness. If new springs, subject to settling have been installed, an additional 1 / 4 maximum thickness is recommended. Brake cylinder measurement gauge (see AAR S-4020) Sample Adjustment Block 2 ¼ Brake Cylinder Measurement Gauge 7/16

Adjustment of Sensor Valve 1 1. Connect the Single Car Test Device as noted in AAR S-486, latest revision. 2. With the branch pipe cut-out cock in the open position, and the test device in the high pressure position, place the test device handle in Position 1.

Adjustment of Sensor Valve 2 3 Ensure there is a blow of air through the car at the opposite end by making sure the angle cock is in the open position. If not already open, use caution when opening the angle cock as shown to avoid injury.

Adjustment of Sensor Valve 3 4. Once this is noted, attach a dummy coupling to the air hose to allow charging of the car air brake system. 5. Place the empty adjustment block under the sensor arm on the truck side frame at a point where the sensor arm will make contact with the block.

Adjustment of Sensor Valve 4 6 Loosen the securement nuts on the adjusting screw. 7 Turn the adjusting screw counterclockwise to extend it and thus allow for adjustment.

Adjustment of Sensor Valve 5 8. Using a 9/16 wrench, remove the plug from the sensor valve body. On older style sensor valves an Allen Wrench may be required to remove the plug. 9 Charge the brake system to a point where the flowrator ball is below the top of the tube.

Adjustment of Sensor Valve 6 10 Move the test device handle to Position 5 and reduce the brake pipe pressure to 60 psi. Slowly move the test device handle back to Position 3 or lap. 11. Brakes must apply as noted by the brake cylinder piston being extended.

Adjustment of Sensor Valve 7 12 The sensor arm must move down and and the contact ball must touch the adjustment block. With the adjustment screw extended there should be no blow of air from the sensor plug hole at this time. If there is, the adjustment screw may have not been turned down far enough or the arm may be damaged or the sensor valve may have failed. 13 Turn in on adjusting screw until a light blow of air is noted at open hole on the sensor valve.

Adjustment of Sensor Valve 8 14. When this is noted, replace the plug in the sensor body. 15. Tighten the adjusting screw securement nuts to the sensor arm to maintain the screw in the correct position.

Adjustment of Sensor Valve 9 16. Carefully remove the adjustment block. 17. Check for leaks at the sensor plug using soap and water, no leakage allowed.

Adjustment of Sensor Valve 10 18 Place test device handle back into Position 1 and note that the brakes release. 19 As the sensor arm rises during the brake release, note air exhausting at vent of sensor valve. This is air allowed into the equalizing reservoir indicating the brakes applied as if the car was empty.

Testing Empty Car/Empty Condition 1 With the car charged to a point where the flowrator ball is below the top of the tube, make a 30 psi reduction in Position 5. Move the test device handle to LAP or Position 3. 2 Make sure sensor arm contact ball touches the side frame and the brakes are applied. Check the brake cylinder pressure measurement gauge. The brake cylinder pressure should be proportionally lower than the loaded brake application pressure depending upon the type of proportional valve. See the Wabtec Single Car Test Manual (WAB/SCT-1) for a chart of empty brake cylinder pressures.

Testing Empty Car/Empty Condition 3. Move test device handle back to Position 1 and recharge the car. 4 Check to ensure the brakes release, the sensor arm raises up and there is a blow from the sensor valve exhaust. Brake Release A Blow of Air Here

Testing Empty Car/Loaded Condition 1 Insert a 2 ¼ block between the truck side frame and the sensor valve contact ball. Check the sensor arm contact ball will touch the block when the brakes are applied. 2 With the brake pipe charged to a point where the flowrator ball is below the top of the tube, move the test device handle to Position 5 and make a 30 psi reduction.

Testing Empty Car/Loaded Condition 3. Slowly move the test device handle to LAP or Position 3. 4. Brakes must apply and sensor contact ball must make contact with 2 ¼ block.

Testing Empty Car/Loaded Condition 5 With the brakes applied, check the brake cylinder pressure as noted on the brake cylinder measurement gauge. Pressure in the brake cylinder should have reached equalization between 60 70 psi.

Testing Empty Car/Loaded Condition 6 Place the test device handle back into Position 1 and recharge the brake pipe. On the release of the brakes note there is no exhaust of air from the exhaust port of the sensor valve. NOTE: In accordance with AAR S-486 the 2 ¼ block must remain in place for part of the brake cylinder leakage test and or the Single Car Test procedure. See AAR Field Manual of Interchange Rules - Rule 3, Chart A for test requirements.

Problems & Troubleshooting 1 Brakes do not apply with a 30 psi reduction. With the control valve operating correctly, air from the control valve is directed to the P-1 Proportional valve. The Proportional valve must function as designed to allow the air pressure to flow to the brake cylinder and the sensor valve. 2 Brakes will not release when the test device handle is returned to Position 1. The sensor valve or the proportional valve may be at fault. The sensor must allow air to exhaust to the proportional valve this is shown by the sensor valve arm moving upward. If the arm does not move up, air is trapped at the proportional valve. If the arm moves up, the air from the brake cylinder will exhaust. 3 During the adjustment of the sensor, air exhausts from the plug hole as soon as the plug is removed. Is the sensor valve adjustment arm contact ball to its maximum extension? If so, the sensor arm may be damaged or the valve may have failed. Change out the valve if no visual defects exist. 4 The sensor arm contact ball is to it s maximum extension and there is air exhausting from the plug hole. The sensor arm may be bent/damaged or the valve may have failed. Change out the valve if no visual defects exist.

Problems & Troubleshooting 5 On a new car application, the brakes apply on a brake pipe reduction but the sensor arm does not move down to contact the side frame. The sensor may be piped incorrectly or the tape/plugs used to protect the valve for shipping were not removed before the sensor was applied. Make necessary repairs and retest. 6 The sensor arm will not move back up to the release position when the brakes release even through the brake piston returns to release position. Is this a problem? Yes, if the sensor arm does not move back up to the release position with an empty car, it will trap air in the equalizing reservoir. On the next empty brake application the pressure in the equalizing reservoir will have higher pressure and could result in higher brake cylinder pressure.

Quiz - Page 1 1. The size of block used to check for loaded operation of a sensor valve when the car is empty is: a. 2 c. 2 1/4 b. 2 5/8 d. 1 3/4 2 On a car with a 60% proportional valve, how much pressure will be directed to the brake cylinder when the car is empty? a. 50% c. 60% b. 40% d. 100% 3 What size adjustment block is used to set the sensor arm for an empty car when the spring travel is unknown? a. 3/4 c. 5/8 b. 7/16 d. 1/4 4. The sensor arm travel can only be set properly on a empty car? True False 5 Add 1/2 shim to the adjustment block when applying all new truck springs. True False 6 The SC-1 Empty/load brake equipment will provide partial braking on a car if it has a partial load. True False

Quiz - Page 2 7. From the diagram on the right side of the page, identify each part or component part by name. A A B C B D E C D F E F

Quiz - Page 3 8. Match the following component to their function by placing the correct letter in front of the statement that best describes its function: A. Truck side frame B. 2 ¼ block C. Securement nuts D. S-1 Sensor Valve E. Proportional Valve F. Equalizing Reservoir G. 7/16 block H. 1/8 block Directs air to the equalizing reservoir for an empty application. Used to set the sensor adjustment on a empty car. Used to hold a portion of the brake cylinder air pressure for an empty application. Holds the S-1 adjusting screw in place. Used to check for loaded operation of the sensor valve on an empty car. Ensures there is the correct percent of air pressure in the brake cylinder for an empty car. A shim added to the adjustment block when lubrication pads are added to the center plate of a car. The contact point for the sensor arm contact ball.

The End If you have questions or comments related to this SC-1/Empty Load equipment Training module, feel free to contact Michael Zenert as listed below. Michael Zenert Manager Air Brake Training Wabtec Global Services 1001 Air Brake Avenue Wilmerding, PA 15148 Phone: 412-825-1453 Fax: 412-825-1499 E-mail: mzenert@wabtec.com Click here to send comments

Quiz Answers 1. C 2. C 3. B 4. True 5. False 6. False A 7. From the diagram on the right side of the page, identify each part or component part by name. B A B C D E F Plug Securement Nuts Contact Ball Sensor Arm Adjustment Block Truck Side Frame F C E D

Quiz Answers 8. Match the following component to their function by placing the correct letter in front of the statement that best describes its function: A. Truck side frame B. 2 ¼ block C. Securement nuts D. S-1 Sensor Valve E. Proportional Valve F. Equalizing Reservoir G. 7/16 block H. 1/8 block D. Directs air to the equalizing reservoir for an empty application. G. Used to set the sensor adjustment on a empty car. F. Used to hold a portion of the brake cylinder air pressure for an empty application. C. Holds the S-1 adjusting screw in place. B. Used to check for loaded operation of the sensor valve on an empty car. E. Ensures there is the correct percent of air pressure in the brake cylinder for an empty car. H. A shim added to the adjustment block when lubrication pads are added to the center plate of a car. A. The contact point for the sensor arm contact ball.

Operation Brake Release/Empty Car Brake Release - Empty 1 Air from the brake cylinder is directed back through the proportional valve to the control valve. 2 With no brake cylinder air at the sensor valve. The sensor valve arm will move up to the release position. 3 The air in the equalizing reservoir is restricted from flowing back to the control valve. Brake Release - Empty Condition Equalizing Reservoir Equalizing Reservoir P-1 Proportional Valve AB Type Control Valve Retainer Valve 4 The air from the equalizing reservoir is allowed to vent out the exhaust port on the bottom of the sensor valve. 5 The sensor arm must move up to the release position thus allowing the air in the equalizing reservoir to escape. This ensures the correct brake cylinder pressure for each successive brake application. Truck Side Frame S-1 Sensor Valve Brake Cylinder Combined Aux. & Emergency Reservoir

S-1 Sensor Adjustment Sensor valve adjustment may be necessary when: The sensor valve is changed in accordance with AAR Rule 4 of the Field Manual of Interchange Rules. See AAR Rule 3, Chart A. The sensor is not providing a correct brake cylinder pressure as noted on the brake cylinder measurement gauge. Pressure must be at least 20 psi lower for an empty brake application versus the loaded full service brake application. (AAR S-486-02) On the brake application of a loaded car, there is air directed to the equalizing reservoir. This will indicate the freight car is braking as an empty car. This is determined by low pressure in the brake cylinder as noted on the brake cylinder measurement gauge during the brake application or an exhaust of air from the sensor valve exhaust on a release of the brakes. Securement Screws Contact Ball Plug Sensor Arm Adjusting Block Truck Side Frame * Components of the S-1 Sensor Valve and the set up of the valve for adjustment purposes are depicted to the right.