What do we name the different Link lines?

A few months ago, Sound Transit backtracked on their decision to name the different Link lines after colors (e.g. Red Line, Blue Line, etc.). This was a wise move for several reasons, among them the history of red-lining in housing, the difficulty of explaining what "red" is to non-English speakers, and potential difficulties for colorblind users.

While Sound Transit have already committed to changing the naming scheme, they have yet to announce what that scheme will be. While many different name examples abound in transit systems around the world, I will contest that naming our rail lines "L-number" (e.g. L1, L2, etc.) is the best for a number of reasons, including local and international consistency, ease of explanation to new users, and simplicity.

Six possible line designators, chosen to be maximally colorblind safe.

Today, our bus-heavy system already uses numbers (the 8) and letters (RapidRide E), meaning any name will need to distinguish itself from those. Since our rail system is regularly referred to as Link Light Rail, naming Link lines L1, L2, and so on will make it easy for users to know that they need a train, not a bus, in a manner consistent with local standards. Additionally, many systems around the world use a similar naming scheme - Barcelona, Munich, Mexico City, Bilbao, and many more cities use a similar pattern. Copying their consensus will make life easier for visitors used to other systems.

Barcelona Metro map

An oft proposed alternative is that used by London and our neighbors in Vancouver - the use of unique line names like Piccadilly and Expo. While such a system is certainly a fun way to give each line more local color (transferring from the "Cobain" to the "Kulshan" line would be a uniquely Seattle experience), explaining the names to non-English speakers would be difficult, as would the inevitably arduous process of choosing what names to use. By contrast, L-names can be explained non-verbally when necessary (numbers and the letter L are trivially easy to sign). Pairing each line with a color (red L1, blue L2) would allow the use of color in explanations when convenient, but without forcing it on the colorblind.

Link lines need names. L-names are an international standard that's locally consistent. L-names are easy to explain in multiple different ways, and L-names are simple - given the recent University Street renaming debacle, a name scheme that appends easily (adding new lines is as easy as adding a new number to the same system) benefits new users and is economical behind the scenes. For system expansion, L-names are as easy as L-1, 2, 3.