The problem is unreliable service and bunching of N's. Running KLM's to
Caltrain would eliminate bunching but this degrades service for riders not
going to Caltrain. Traffic signal override reduces travel time but does
not address bunching or reliability problems.
Muni Metro service is unreliable. Walking is very reliable, but not
feasible for many. The 30/45 buses might a viable alternative for those
near the Powell and Montgomery St Stations. The N is very convenient for
those near Embarcadero Station. The ideal solution is to extend Caltrain
to the Transbay Terminal.
I recall that Muni planned to eliminate express bus service to Caltrain
when E-line (now N) service was started. But there was an uproar and Muni
would study the new ridership patterns before eliminating the service. Has
the bus service been cut?