The terrible logistics of the Muni Metro subway system — which Muni did not even design themselves — are in line for an overhaul as the SFMTA tries to get its rail service back on track.

A fun (but facepalm-inducing) fact about Muni’s almost daily rush hour meltdowns is that the underground tunnels are inefficiently designed in part because Muni did not even design them. BART designed much of the Muni Metro system, apparently with little success getting feedback or input from Muni, which was under-funded and indecisive at the time the tunnels were getting designed. In the late 70s and early 80s when the current underground tunnel system was being planned and constructed, Muni failed to inform BART of very fundamental decisions like what kind of trains they planned to use in the tunnels ,or the types of platforms they needed. “Muni had not decided how they would operate the tunnels,” transit activist and historian Rick Laubscher said at a June SFMTA Board of Directors meeting. “BART was flying blind.”

These issues are coming to light again as Mayor Breed’s task force to fix Muni looks at the rail system’s root problems, and the San Francisco Examiner reports that they’ve identified a big one that most of us already are too familiar with — that one broken train can bottleneck the entire system at rush hour because there are essentially no turnarounds or alternate tracks.

In cities like New York and Los Angeles, major stations have multiple tracks for a single rail line, including express train tracks that run parallel to the main ones. If one train breaks, the others can simply keep running on an alternate track. Other cities like Berlin, Paris, and Washington, DC have rails designed with “trunks” and “turnbacks” that make it very easy to clear a disabled train.

“We have neither of those designs,” said acting S.F. transit director Julie Kirschbaum, speaking to the SFMTA board. “That’s the cause of the bottleneck.”

“The subway itself was not designed with train turning movements in mind,” she explained.

One solution Kirschbaum has identified is to build “pocket tracks,” or alternate tracks where a malfunctioning train can be pulled aside so others can continue their routes uninterrupted. The good news is that Muni has identified several potential sites to install pocket tracks; the bad news is that these would take at least three to seven years to build.

All of this comes against the backdrop of the long-delayed Central Subway system continuing to be long-delayed, and the SFMTA itself still not having a permanent director after Ed Reiskin’s sudden departure this spring. (The SFMTA board search committee will be meeting on that topic this week). But it also shows how many of Muni’s problems are historical and not entirely the fault of current management or engineering — and reminds us that even in the 70s and 80s, Muni did not have its act together.

Related: Muni’s July 1 Fare Increase For Cash-Paying Riders Not Sitting Well With Cash-Paying Riders [SFist]