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7 Cards in this Set
- Front
- Back
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What is the purpose of the 26L automatic brake valve? |
Type 26L brake equipment has a number of components the driver will use during train running, brake valve testing and emergency situations. Such components are: - air pressure gauges - air flow indicator, main reservoir - red needle & equalizing reservoir - white needle, brake cylinder No1 & No2 bogies, and brake pipe - air flow meter and indicator - detects irregular reduction in brake pipe pressure and monitors recharging rate of the brake pipe following a release of the automatic break - indications are audible & visual - brake pipe emergency cock - in the event of brake valve failure, emergency cock can exhaust brake pipe pressure to atmosphere |
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What are the six operating positions of the 26L automatic brake valve? |
1. Release 2. Minimum reduction 3. Full service 4. Suppression 5. Handle off 6. Emergency |
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What is the purpose of the regulating valve? |
The regulating valve maintains brake pipe pressure at 500 KPA whilst the automatic brake valve is in the release position. The reduction of equalising reservoir in turn causes an equivalent reduction in brake pipe pressure. The purpose of the regulating valve is to: - charge and maintain equalizing reservoir and brake pipe pressure at 500 K PA whilst the automatic brake valve is in the release position OR - initiate an application of the automatic brake by the reduction of equalizing reservoir pressure |
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What is the purpose of each position of the 26L automatic brake valve? |
1. Release - Release the brakes throughout the train and charge brake pipe pressure to 500 K PA AND - maintain brake pipe pressure at 500 K PA against reasonable leakage 2. Minimum reduction - Initiate an automatic application (minimum reduction-50KPa) of the air brake throughout the train 3. Full service - obtains a full service reduction of brake pipe pressure - a reduction of up to 175kPa (BP-reduced to 325kPa) - the application of the brake is termed as fully equalized application throughout the train 4. Suppression - obtain a full service reduction of brake pipe pressure (reduction of 175kPa) AND suppress the VC 5. Handle off - reduce brake pipe pressure to70 kPa, render VC inoperative AND allow removal of the brake valve operating handle 6. Emergency - brake pipe pressure reduces to 0kPa and airbrakes throughout the train shall fully apply at the maximum possible rate - driver must leave handle in the emergency position until the train has come to a complete stand |
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What is the purpose of the brake valve cut off valve and what are its two operating positions? |
The brake valve cut off valve is used to isolate the connection between the main reservoir and the 26L automatic brake valve. The cut off valve has two positions: - IN - OUT |
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What is the purpose of the brake pipe maintaining feature? |
Should break pipe leakage exist, the braking effort of the train will progressively increase by more than the amount the driver had intended. The 26L automatic brake valve is provided with a brake pipe pressure maintaining feature. When the driver moves the operating handle of the 26L automatic brake valve to the APPLICATION ZONE, the brake pipe pressure maintaining feature ensures that the brake pipe pressure will remain set at the desired reduction and maintained against reasonable brake pipe leakage. |
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What are the operating features and requirements of the 26L automatic brake? |
The 26L automatic brake valve is a self lapping valve. Moving the operating handle through the SERVICE APPLICATION ZONE provides a brake pipe reduction between 50 and 175 KPA proportionate to the movement of the valve. A pressure maintaining feature ensures that brake pipe reductions are maintained against reasonable leakage whilst the airbrake is applied on the train. When the operating handle of the brake valve is placed in the RELEASE position the recharging of the brake pipe is controlled by the regulating valve - similar to the M3 feed valve in conjunction with the No4 brake equipment. |
