It's definitely evident whenever I ride the trains, but remember, the T1s had some really bad noise issues back when Andy Byford took over as CEO of the TTC. If anything, it's probably just due to their age and the fact that the TRs undergo less maintenance than the T1s. It's probably just a pin connection that needs some lubricant in most cases, I doubt it's a serious fault in the construction of the TRs (Despite Bombardier's notorious reputation for quality). If people complain enough, the TTC will probably notice.