MUNI naming scheme
August 8, 2008 5:25 PM   Subscribe

Why does MUNI sometimes call a train N and sometimes N N? Where can I learn more about their naming schemes?

I've taken the occasional light rail in SF without really understanding the announcer in subway stations. I didn't notice a connection between the double letters and whether a train has multiple cars, or whether it's inbound or outbound, but maybe I've missed something obvious.

What does it mean, and where can I read about MUNI? For example, I've also been wondering why my station announces "Embarcadero" and "Mission Bay" for inbound trains but specifies the letter for outbound trains.
posted by scission to Travel & Transportation (13 answers total)
Check out SFMTA for all your muni related questions.

Are you sure there was no connection between double letters and multiple cars? I always assumed that's what it was but I'm not completely sure.

The inbound trains specify Embarcadero or Mission Bay because only some of them go past Embarcadero down the 3rd street corridor. This is the T line and I believe all trains are called T once they come out of the ground on that side of Embarcadero. But I don't ride over there much so I'm not sure about that, either.
posted by rkent at 5:45 PM on August 8, 2008

I believe it does in fact reflect how many cars there are on a particular train? That is, an N would be a single car while NN would be two.

As for your question on inbounds, it doesn't matter what line they are because they all end up at the same place: either Mission Bay or Embarcadero. Knowing which line it is would tell you only where it came from and nothing about where it's going.

(Caveat: This is from memory; I left SF three years ago.)
posted by donpedro at 5:45 PM on August 8, 2008

I left SF three years ago too, but I seem to remember that two letters refers to two cars, and one for one. Not sure why they do that, but hey.
posted by the dief at 5:54 PM on August 8, 2008

Best answer: N = one car N Judah train
NN = two car N Judah train

same for the other lines: L = one car L; MM = two car M.

donpedro is correct about the inbound trains. There are only 2 options for inbound trains (setting aside the T) so they only announce those options. There are more options for outbound trains (J, K, L, M, N) so that level of detail is specified.
posted by gingerbeer at 6:03 PM on August 8, 2008

Best answer: Also, if you want to read more about Muni beyond the SFMTA site linked above, try the N Judah Chronicles, Muni Diaries, Rescue Muni,, the Transbay Blog, and SFist's Muni coverage (which is annoyingly not accessible through the use of their "Muni" tag).
posted by gingerbeer at 6:14 PM on August 8, 2008

Response by poster: Obviously I haven't been listening to the MUNI announcers as closely as I thought. Thanks, everyone! I'm leaving the city soon, so gingerbeer's links will have to keep me occupied for now.

(Although, if anyone's still reading... why use double letters some of the time and say "one car" or "two car" other times?)
posted by scission at 6:36 PM on August 8, 2008

why use double letters some of the time and say "one car" or "two car" other times?

Actually, I think they usually do both at the same time; e.g., "Approaching...Outbound...two car...N N...followed car...L". This redundancy has always bothered me and I have no idea why they do it.
posted by epugachev at 6:45 PM on August 8, 2008

Another thing to pay attention to is the chime before they announce the train. It's a two-tone chime that's either descending or ascending, depending on whether the train is inbound or outbound.
posted by Jeff Howard at 8:18 PM on August 8, 2008

Best answer: " "Approaching...Outbound...two car...N N...followed car...L". This redundancy has always bothered me and I have no idea why they do it."

Because a long long time ago, before the screaming Italian cars, before the train automation meltdown, K/L/M metro traffic through West Portal would be combined for the tunnel portion of the run. You'd catch a KKM train downtown (back when trains of longer than two cars were run at a time) and then sit around for a couple of minutes at West Portal for it to split into one KK and one M train at West Portal. I don't know when they stopped doing this; I wasn't living along a metro line for the better part of a decade, and then moved out of the City.

They don't do that any more, but I think it's a matter of current practice, not policy. Thus all the hardware is set up to support the possibility that mixed trains might have to be announced thus: "Outbound. Four car. K, K, L, M. Followed by... fifty!... minutes of empty tunnel."
posted by majick at 11:20 PM on August 8, 2008 [2 favorites]

majick is correct about the reason for the redundancy in the announcements. (I thought I was the only one who remembered that!) As far as I recall, they stopped doing it when they got rid of the old green trains. (I could be wrong about that.)

Also be aware that, for reasons unknown to me, the outbound announcements these days are incorrect in the downtown stations almost half the time (in my experience), at least during evening rush hour. Check the route designation on the front of the train before you board.
posted by trip and a half at 7:29 AM on August 9, 2008

Oops. To clarify, I mean the "...followed by..." part of the outbound announcements is often incorrect.
posted by trip and a half at 7:35 AM on August 9, 2008

"As far as I recall, they stopped doing it when they got rid of the old green trains. (I could be wrong about that."

I'm absolutely certain this practice continued into the late 80s with the Boeing cars, after the green cars were pretty much completely retired. My father in law drove metro cars when all cable cars were out of service during the big cable car renovation, I'll ask him about it and see if he remembers more closely when they stopped coupling and decoupling at West Portal. But if I had to guess from memory I'd peg this as still happening at least as late as 1988 (when I lived out on 45th and Vicente and rode a lot of L) and possibly into the early 90s.
posted by majick at 8:26 AM on August 9, 2008

Of possible interest is, which contains both a live snapshot and an explanation of that cryptic Muni map that you see in most of the downtown stations. Fun fact: the whole thing is generated by having a web cam(!) pointed at a screen somewhere in the Muni control station.
posted by whir at 11:23 AM on August 10, 2008 [1 favorite]

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