I didn't say that they don't fail. I said that distance is not a problem.
How often have we seen loco failures for TN or any of the long distance trains? A lot of trains in NCR do 130kmph runs regularly. We don't see regular failures on them.
Even...
more... wit the old WAP4/WAM4 locos, which had DC motors that were more susceptible to failure, failures on regular runs were uncommon. 3 Phasers have a much simpler motor design which makes them suitable for long distance runs and they don't even need serious maintenance at their home shed for long intervals.
Locos can fail for a variety of reasons. Yes, running for longer distances increases the chance of a failure, but the 3 phasers are designed to run long distances without any issues. So, it isn't a problem for speeding up TN.