Post by darwins on Nov 7, 2022 7:39:12 GMT
Mercury retarders followed on from the introduction of EP brakes and were first fitted to standard stock in the 1930s.
I know that in a slightly more sophisticated form they were still part of the equipment of the 1967 Victoria Line stock.
The retarders limited the maximum rate of EP braking (and emergency braking). Can anyone provide a figure for the intended maximum deceleration rate? (mph/s or m/s/s or ft/s/s)?
Presumably for some years now, perhaps from 1970s or 1980s more modern electronic "Wheel Slide Protection" has replaced them. (Together with load compensation.)
WSP in its mainline form simply prevents wheels from locking, depending on rail conditions. It does not control the maximum rate of deceleration. Is there any device in more modern stock that limits the rate of service braking?
Just found some numbers.
The Queen's Park 1949 accident report says:
"The EP brake is designed to effect a retardation of 2.6 mph per second, and a full application of the Westinghouse Automatic brake, or the release of the 'dead man's handle', gives greater retardation up to the limit of adhesion."
Brake tests from the Stratford 1953 accident report give an average deceleration rate of 1.7 mph per second using the emergency brake.
posts merged - Dstock7080
I know that in a slightly more sophisticated form they were still part of the equipment of the 1967 Victoria Line stock.
The retarders limited the maximum rate of EP braking (and emergency braking). Can anyone provide a figure for the intended maximum deceleration rate? (mph/s or m/s/s or ft/s/s)?
Presumably for some years now, perhaps from 1970s or 1980s more modern electronic "Wheel Slide Protection" has replaced them. (Together with load compensation.)
WSP in its mainline form simply prevents wheels from locking, depending on rail conditions. It does not control the maximum rate of deceleration. Is there any device in more modern stock that limits the rate of service braking?
Just found some numbers.
The Queen's Park 1949 accident report says:
"The EP brake is designed to effect a retardation of 2.6 mph per second, and a full application of the Westinghouse Automatic brake, or the release of the 'dead man's handle', gives greater retardation up to the limit of adhesion."
Brake tests from the Stratford 1953 accident report give an average deceleration rate of 1.7 mph per second using the emergency brake.
posts merged - Dstock7080
