I've been a reader and occasional commenter in Alon Levy's blog for some time. He is worth reading.
I had just read that post and was thinking about it. I've had to deal with the phenomenon that he describes. For example, the W-Line (Denver - Lakewood - Golden) needed pre-pandemic an extra all-day train (2 or 3 LRV's) due to Quiet Crossings agreed to after construction began, as well as some speed restrictions. The slower runtime therefore had not been included in the ridership modeling or the budget for rolling stock nor the projected labor costs. But, it may have made the neighbors happier.
Levy did not get into the worse similar situation on bus routes. In our meetings with other big system operations planners there evolved a consensus that a bus system that is not growing in hours of service by 1 to 2 percent a year must make minor service reductions to pay for increased costs elsewhere in the system. Every year new traffic signals are added, congestion increases, businesses relocate, access to restrooms for drivers is suddenly revoked, etc.
That happened repeatedly in Denver with no-growth budgets. For example, against my advice, the City of Wheat Ridge rebuilt West 38th Avenue with bus pull-outs at every stop. We didn't object to pull-outs where buses had long dwell times but there was a 10% increase in running time as a result of doing it at every stop. That had to be paid for somehow with a no-growth budget.
Ironically, one of the reasons to build rail lines is to get out of that sort of thing. It sabotages that function when slowdowns are imposed on rail systems without considering other solutions or even compromises.
