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| Re: Photos: BMT ''C'' Types (884395) | |||
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Re: Photos: BMT ''C'' Types |
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Posted by Jeff H. on Sat Jan 9 22:05:13 2010, in response to Re: Photos: BMT ''C'' Types, posted by randyo on Sat Jan 9 05:12:03 2010. Randy,I'm looking at the WABCO instruction pamphlet dated 1929 describing the AMUE system with ME30 brake valve as applied to the IRT. The cut of the ME-30 shows the same standard 4 fingers (battery, apply, release, emergency) as an ME-23. There is no indication anywhere in the manual about this "charging" feature. The primary difference in the drawings between the ME23 and ME30 is pneumatic: The ME23 had vestigal ports for brake cylinder exhaust which was a feature never used with AMUE, but something that might have been active when using the valve as an M23, e.g. several interurban properties. The other pneumatic difference is that the ME30 has a separate port for a feed valve control pipe. This is used in conjunction with the type "L" feed valve to monitor the actual pressure being delivered into the brake pipe, rather than just the delivery pressure leaving the feed valve. I would tend to believe that this "electric charging" feature is a misunderstanding. Interestingly, on the D types, there is an extra finger in the ME23, but it is used to ground a specific trainline wire in emergency which in turn enables reset of the E/P trainline emergency wire. The effect of this is to require the m/m to place the handle in emergency to acknowledge a trip application before being able to reset it. The same contact was also used on the group boxes to bypass the Potential Relay function and allow the motors to be "plugged" by having the reversers throw and the group run up to parallel |
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