The abbreviation CRRT may refer to Cristopher Reuel Tolkien Carrier Route mail sorting system for the United States Postal Service Continuous renal replacement therapy Chemical-Biological-Radiological Rapid Response Team Commuter Rail Real Time data from the MBTA, providing train locations and arrival predictions for the MBTA Commuter Rail system Cyber Rapid Response Team - EU countries (Lithuania, Estonia, Croatia, Poland, the Netherlands and Romania) cooperation in cyber area