On CO flight 62 yesterday from IAH to EWR the pilot announced that there was a brake lock problem and that he put the landing gear down for awhile after take off. Then when we landed we were met by fire trucks who examined things, but there were no problems. The landing was smooth and although we were told that we were going to land in an emergency way, we didn't have to bend over and brace ourselves or anything, it seemed to me a normal landing. The same plane was due to continue on to Madrid but they seem to have replaced that flight with a different plane. I'm curious as to how common this sort of problem is and why lowering the landing gear helped. The FAs and pilot were excellent on the flight from my impression.