It's a tale as old as time in these parts, but everyone's morning commute on Muni was pretty miserable on Thursday when the metro system's automatic train controls pooped out.

Giving their usual excuses about upgrades in progress, the SFMTA said vaguely and repeatedly on Twitter that this morning's meltdown was due to "mechanical issues."

The Examiner reports, via the SFMTA, that today's issues were with the automatic train controls, and the underground system was operating at "walking speeds" because drivers had to control the trains manually — an excuse, to this day, I will never understand but has something to do with safety.

After SFMTA acting Director of Transit Julie Kirschbaum told the Chronicle last week that she's committing to cutting systemwide delays by a meager 10 percent, Curbed laid out the numbers in terms of each train line's on-time percentage. For example, the K/T-Third Street line is late or very late 45 percent of the time, and the M-Oceanview is currently late or very late 57 percent of the time.

The San Francisco city charter, meanwhile, mandates that Muni maintain an 85-percent on-time rating. [Editor's note: Have they ever even been close to that?]

SFist last looked at Muni's on-time rating in 2014, when it was hovering around 60% — after a then all-time low of 57.4% in October 2013. The new low, as of January 2019, is 55% — meaning that buses and trains, on average, are no more than four minutes late or one minute early 55% of the time.

Earlier this week the Chronicle reported that Muni was trying put its recent delay issues "under a microscope."

Lots and lots of commuters were late to work this morning as a result of Muni's all too familiar jackassery, and despite their running some shuttle buses above ground. Below is the social media evidence.