With the Purple Line’s future looking brighter, it is finally becoming easier to envision the embattled light rail line becoming a reality. But if the line does become a part of our region’s transit network, will it also be a part of the iconic Metro map?

Base map by Peter Dovak, cartoony additions by David Alpert.

While it’s called the “Purple Line,” WMATA would not be building this line, nor was it planned as a part of the Metrorail system. It’s still unclear how well the line would integrate with other lines. There hasn’t ever been a decision made about whether, for example, you’ll pay a separate fare to ride the Purple Line, as with a bus, or whether it will be part of the same fare structure as all of the rail lines.

Advocates and planners have long shown images of the Purple Line on Metro map to help cement the idea that this new line will become a critical component of the region’s rail transit. But it isn’t trivial to fit the line into the existing Metro map.

An older diagram of the Purple Line atop the base WMATA Map via Coalition for Smarter Growth.

How can the Purple Line fit?

If it appears on the map, the Purple Line would be the just the second line color to go on the map since the system’s inception, besides the Silver Line. Unlike the Silver, though, the Purple Line and its winding route among the branches of the Metro system will force significant changes to fit with the map’s chunky, iconic style.

The map’s diagrammatic nature distorts the system heavily as the lines spread outside the core. Simply adding the line itself in and making minor modifications to label placement actually works fairly well, but it's tough to squeeze 10 Purple Line stations into the space between Silver Spring and College Park, while there are only three between Silver Spring and Bethesda.

People might assume, from the above map, that the stations east of Silver Spring are very close together, and very far apart to the west. But that’s not true. Instead, the two branches of the Red Line are much closer together than the map suggests.

One solution is to shift the Green/Rush Yellow segment north of Fort Totten to the east. While this more accurately reflects the route through Prince George’s County, the change would be one of the most significant to the map since its creation in the 1970s, and may perhaps be a controversial one.

Should the Purple Line get equal billing to heavy rail lines?

The Purple Line is not a Metrorail line. It is a light rail line. And WMATA might not even operate it. Arguably, therefore, the Purple Line should appear less important than the six Metrorail lines.

Today’s map doesn’t even show other rail services like Amtrak, MARC and VRE. They only get logos next to their respective transfer points. But far more people will likely transfer to and from the Purple Line, and it will run much more frequently than commuter rail or Amtrak. Just using icons would not make the Purple Line very visible. On smaller printed or web versions of the map, they may be difficult to spot at all.

The map could display the Purple Line but in a different style. A thinner line, using smaller station labels, or only showing the line itself and not the stations are all possible solutions.

Most other American cities with multimodal rail transit do not bother to make this distinction, however. Los Angeles, Philadelphia, and Boston all operate light and heavy rail (though under the same agency) and display them no differently.

What about other services?

If and how to show the Purple Line will likely depend on who operates the system, its ridership, differences in fares or operating hours, and many other factors. After decades of campaigning, though, many would agree that the Purple Line deserves a spot on the Metro map, but it is still a topic that raises an interesting discussion.

And if the Purple Line is deserving, what about MetroWay, DC Streetcar, or the multitude of planned BRT lines? Should it show commuter rail, akin to Philadelphia and Boston’s transit maps? What makes a service deserving? These are questions Metro leaders and the region will have to grapple with if the Purple Line becomes a reality.