CMRR may stand for:
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Catskill Mountain Railroad
The Catskill Mountain Railroad is a heritage tourist railroad based in Kingston, New York, that began operations in 1982.
The railroad leases a 4.7-mile portion (MP 3.6 to MP 8.3) of the former New York Central Railroad Catskill Mountain br ...
, operators of the former New York Central Railroad Catskill Mountain Branch from Kingston to Phoenicia
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Central Massachusetts Railroad, former railroad forming part of the Boston and Maine Railroad system
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Common-mode rejection ratio, measure of the capability of an instrument to reject a signal that is common to both input leads
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Chemistry and Metallurgy Research Replacement Facility, nuclear facility at Los Alamos National Laboratory
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