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Re: Q about retainers in general
Author: SP5103
Date: 01-01-2014 - 12:05
Modern retainers are made out of plastic.
Here is the 2012 Union Pacific rule regarding retainers:
34.5.5: Retaining Valves
Retainers may only be used after consulting with a Manager of Operating Practices for the location involved.
When retaining valves are used:
Retaining valves must be set in the "HP" (High Pressure) position on the entire train.
Do not exceed 15 MPH.
Freight car brake cylinder pressure is not retained until a brake pipe reduction of at least 10-psi has been made and released. Further brake pipe reductions will add to this pressure in the brake cylinder.
When retaining valves are not in use, place them in EX(Exhaust).
Is anyone even teaching retainer use to engineers these days, or on simulators?
The use of HP (20 psi) on empties has been traditionally avoided, and modern retainers (since 1967) have a SD (Slow Direct) position that is usually used for empty cars. In any position other than EX, the retainer chokes the brake cylinder exhaust to require about twice as long to release.
Here is another odd UP rule:
34.5.6: Use of Automatic Brakes During Cold Weather Conditions
49 CFR 232.107
During extreme cold weather, (below 10 degrees F) when operating conditions and outstanding instructions permit, throttle manipulations and dynamic braking must be used in lieu of train air brakes whenever possible in controlling and stopping freight trains.
Evidently UP prefers to have the entire air brake rigging frozen in ice rather than potentially deal with a few stuck brakes. Evidently this is part of their compliance with 49 CFR 232.107 since the UP rule references it.
§ 232.107
Air source requirements and cold weather operations.
(a) Monitoring plans for yard air sources. (1) A railroad shall adopt and comply with a written plan to monitor all yard air sources, other than locomotives, to determine that they operate as intended and do not introduce contaminants into the brake system of freight equipment.
(2) This plan shall require the railroad to:
(i) Inspect each yard air source at least two times per calendar year, no less than five months apart, to determine it operates as intended and does not introduce contaminants into the brake system of the equipment it services.
(ii) Identify yard air sources found not to be operating as intended or found introducing contaminants into the brake system of the equipment it services.
(iii) Repair or take other remedial action regarding any yard air source identified under paragraph (a)(2)(ii) of this section.
(3) A railroad shall maintain records of the information and actions required by paragraph (a)(2). These records shall be maintained for a period of at least one year from the date of creation and may be maintained either electronically or in writing.
(b) Condensation and other contaminants shall be blown from the pipe or hose from which compressed air is taken prior to connecting the yard air line or motive power to the train.
(c) No chemicals which are known to degrade or harm brake system components shall be placed in the train air brake system.
(d) Yard air reservoirs shall either be equipped with an operable automatic drain system or be manually drained at least once each day that the devices are used or more often if moisture is detected in the system.
(e) A railroad shall adopt and comply with detailed written operating procedures tailored to the equipment and territory of that railroad to cover safe train operations during cold weather. For purposes of this provision, “cold weather” means when the ambient temperature drops below 10 degrees Fahrenheit (F) (minus 12.2 degrees Celsius).
Here is the 2012 Union Pacific rule regarding retainers:
34.5.5: Retaining Valves
Retainers may only be used after consulting with a Manager of Operating Practices for the location involved.
When retaining valves are used:
Retaining valves must be set in the "HP" (High Pressure) position on the entire train.
Do not exceed 15 MPH.
Freight car brake cylinder pressure is not retained until a brake pipe reduction of at least 10-psi has been made and released. Further brake pipe reductions will add to this pressure in the brake cylinder.
When retaining valves are not in use, place them in EX(Exhaust).
Is anyone even teaching retainer use to engineers these days, or on simulators?
The use of HP (20 psi) on empties has been traditionally avoided, and modern retainers (since 1967) have a SD (Slow Direct) position that is usually used for empty cars. In any position other than EX, the retainer chokes the brake cylinder exhaust to require about twice as long to release.
Here is another odd UP rule:
34.5.6: Use of Automatic Brakes During Cold Weather Conditions
49 CFR 232.107
During extreme cold weather, (below 10 degrees F) when operating conditions and outstanding instructions permit, throttle manipulations and dynamic braking must be used in lieu of train air brakes whenever possible in controlling and stopping freight trains.
Evidently UP prefers to have the entire air brake rigging frozen in ice rather than potentially deal with a few stuck brakes. Evidently this is part of their compliance with 49 CFR 232.107 since the UP rule references it.
§ 232.107
Air source requirements and cold weather operations.
(a) Monitoring plans for yard air sources. (1) A railroad shall adopt and comply with a written plan to monitor all yard air sources, other than locomotives, to determine that they operate as intended and do not introduce contaminants into the brake system of freight equipment.
(2) This plan shall require the railroad to:
(i) Inspect each yard air source at least two times per calendar year, no less than five months apart, to determine it operates as intended and does not introduce contaminants into the brake system of the equipment it services.
(ii) Identify yard air sources found not to be operating as intended or found introducing contaminants into the brake system of the equipment it services.
(iii) Repair or take other remedial action regarding any yard air source identified under paragraph (a)(2)(ii) of this section.
(3) A railroad shall maintain records of the information and actions required by paragraph (a)(2). These records shall be maintained for a period of at least one year from the date of creation and may be maintained either electronically or in writing.
(b) Condensation and other contaminants shall be blown from the pipe or hose from which compressed air is taken prior to connecting the yard air line or motive power to the train.
(c) No chemicals which are known to degrade or harm brake system components shall be placed in the train air brake system.
(d) Yard air reservoirs shall either be equipped with an operable automatic drain system or be manually drained at least once each day that the devices are used or more often if moisture is detected in the system.
(e) A railroad shall adopt and comply with detailed written operating procedures tailored to the equipment and territory of that railroad to cover safe train operations during cold weather. For purposes of this provision, “cold weather” means when the ambient temperature drops below 10 degrees Fahrenheit (F) (minus 12.2 degrees Celsius).
