Three Brooklyn Supreme Court judges have been transferred to new posts in other boroughs for, according to sources, falling behind on their caseloads, not holding enough trial days and spending too much time away from the bench.

This month, Justices Bruce Balter, Cassandra Mullen and Shawndya Simpson, who each presided over criminal parts, were sent to new posts for “operational” reasons, said Lucian Chalfen, a spokesman for the Office of Court Administration, who declined to further elaborate on the reason.