We usually call Sounder “regional rail” or “commuter rail”, but both terms are ambiguous. Other possible terms like “metropolitan rail”, “local rail”, “express rail”, or “rapid transit” are also ambiguous. That leaves me at a loss with what to call Sounder or RER that’s not ambiguous. The same problem exists with Cascades.

“Regional rail” implies an area with multiple political entities. Both Sounder and Cascades are called “regional rail” but are at different scales. Sounder goes out 50 miles like Caltrain, connecting suburbs and cities within a multipolar metropolitan area. Cascades is 500 miles long, connecting multiple nearby metropolitan areas. High-speed rail plays a similar role. So we need distinct words for Sounder-type networks and Cascades-type networks.

“Metropolitan rail” implies the city and suburbs within an metropolitan area. This sounds like Sounder, except the term “metropolitan” has been monopolized by subways. Subways are shorter, have closer stop spacing, and higher frequency. Paris has both RER and metro, making this distinction between them.

“Commuter rail” originally meant riding on a “communtation ticket”, or multi-trip discount ticket like a 10-pack. This has led to a bifurcation, with some commuter rails running full time and others peak-only Caltrain and PATH run full time bidirectionally, so they’re as good for a weekend trip to the museum as a weekday trip to the office. They’re intended to capture the bulk of trips in their area to minimize driving, both work trips and other trips. Other commuter rail network are peak only, serving only 9-5 downtown office workers, and there’s resistance to expanding them to other uses.

“Rapid transit” to me means faster than a regular bus, so grade-separated, wider stop spacing, and higher frequency. Others use the term specifically for third-rail or heavy-rail metros.

Some people use “S-Bahn” or “RER” generically to refer to this mid-level service, but most Americans have never heard of those and don’t know what they are.

So is there a unique and unambiguous way to refer to Sounder, RER, S-Bahn type rail? Something that gets at the four-way distinction between Link, Sounder, Cascades, and intercity lines? Because “regional” is too ambiguous.

23 Replies to “What to call Sounder-type rail?”

  1. For me, as long as Sounder runs in a single direction at commute hours only, it’s “commuter” rail. It’s impractical for most people unless they are literally commuting to work or school.

    Similarly, if a bus route runs in only one direction at each commute period, I think of it as a commuter bus.

    In other words, I think that it’s the operation more than the vehicle that differentiates the term “commuter” transit.


    I like the term “regional rail” for services that run all day in both direction, even if the service is just every hour or two. Everything from CalTrain to Cascades seem to fall into this category.

    I’m not a fan of “suburban rail” as that refers to a land use concept rather than a transportation one.

    1. Sounder runs in both directions during the ‘commute window,’ but otherwise I agree. Sounder could electrify and switch to a totally different rolling stock, but it would still be commute rail. As long as it runs primarily during typical commute hours, I think Commuter Rail is a good term.

      If Sounder is able to expand into most-of-the-day operations, then I think Regional Rail is a good term.

  2. Cascades is very firmly intercity rail. It goes between cities with distinct metropolitan area boundaries.

    Sounder is unambiguously commuter rail, because it does not run all day in both directions.

    1. “Cascades is very firmly intercity rail.”

      How do you distinguish Cascades from the Coast Starlight and Empire Builder then? Portland and Vancouver are distinct metros but they’re within the Pacific Northwest. Intercity tends to mean metros in different regions. We might call them “national rail” because the Coast Starlight crosses the entire country, but the Empire Builder crosses only half the country.

      1. Long-distance.

        The Europeans regularly refer to their multiple city routes as Intercity. American states are the sizes of European countries.

        Continental scale long distance routes for the most part do not exist in the EU or Japan.

      2. I think there has to be a distinguishing of what kinds of food and sleeping options are available on a particular service.

        1. Regional rail or S-Bahns don’t have dining cars.

        2. Cascades offer something more significant. They have dining cars but not sleeping berths. I’d be fine with inter-city rail or regional rail.

        3. Something with both a dining car and sleeping berths is definitely “cross country” rail.

      3. I’d define transit levels in multiple categories

        Local – all-day service that has multiple stops that are spaced generally short distances from each other, can be one or two blocks up to a mile at most. Seating is dense to move more people quickly. Frequency being generally 2-4 tph at minimum, but commonly is more depending on the route.

        Regional – all-day service that serves the city, the outlying suburbs, and sometimes exurbs with service into the city or around the city depending on the size (see Berlin S Bahn). Can sometimes string multiple large cities together (UTA FrontRunner connecting Ogden, Salt Lake City, and Provo). Usually has a pattern of multiple stops spaced close together in the main city center and then are farther spaced the farther you go out, sometimes a mile to upwards of 5-10 miles. Lower passanger capacity, less dense seating, may include luggage storage or bag racks above seat or somewhere in the vehicle. Frequency is commonly 2-4 tph but can be much higher on heavily used routes or when interlined in the city center. May also have express service on some routes (Paris RER B CDG Express runs north of Gare du Nord)

        Commuter – service that is generally peak only, services smaller populated outer burbs or exurbs, has limited runs, or specialized routes that serve a specific destination (Boeing Everett Plant, First Hill, School Routes, etc). Generally more comfortable, less seating, and frequency of 1-2 tph in the peak direction.

        Intercity – strings together multiple cities with each other, with a mix of large, medium, small cities, and important destinations (airports, ferry ports, border crossings, etc) together as stops along the line. Contains more comfortable seating, usually a dining or café car, single or multiple travel classes, bathrooms, ans luggage storage. And usually has a frequency of 1-2 tph in each direction.

        Long Distance/Cross County/International (EU) – Trains that have overnight or night train service (in the case of the EU). Similar to intercity in terms of destination mix. Similar comforts of intercity, with the added addition of sleeping cars. May arrive at some destinations at odd hours in the middle of the night. Usually served by one or two trains per day in each direction.

        The thing about these service levels is that they are just broad definitions and some transit operator may use a mix of them on any given service. Like the Berlin S Bahn or Copenhagen/Southern Sweden Øresundtåg system has a unique blend of city/regional (S-Bahn) and regional/intercity (Øresundståg) respectively.

      4. In Berlin, the S-Bahn is much like Link (only smaller stations but with longer platforms). The next step up is the Re-1 and Rb trains, which serves both commuter needs and shorter distance intercity, with a premium class car and food services available. There are frequent stops like Sounder, but end of line to end of line the average speed is a bit faster than Sounder, with the Re-1 averaging about 70 mph over its length, or faster than Cascades.

        There is no concept of a dedicated train that is only used two hours per day, weekdays only.

      5. Zach lays it out well.

        Another good examples of regional rail that connect non-contiguous cities is Rail Runner (Albuquerque to Santa Fe), but interestingly both Rail Runner and Front Runner (Utah) are commuter rail as defined by APTA: https://en.wikipedia.org/wiki/List_of_United_States_commuter_rail_systems_by_ridership

        But then the Hiawatha – a regular service between Milwaukee and Chicago – is called inter-city by Wikipedia, probably only because it is operated by Amtrak rather than a state agency like the other examples. https://en.wikipedia.org/wiki/Hiawatha_Service

      6. The commuter rail article linked from there has some helpful terminology.

        “[Commuter rail is] primarily for short-distance (local) travel between a central business district and adjacent suburbs and regional travel between cities of a conurbation. It does not include rapid transit or light rail service.”

        “Many, but not all, newer commuter railways offer service during peak times only, with trains into the central business district during morning rush hour and returning to the outer areas during the evening rush hour…. Other commuter rail services, many of them older, long-established ones, operate seven days a week, with service from early morning to after midnight.”

        “After the completion of SEPTA Regional Rail’s Center City Commuter Connection in 1981, which allowed through-running between two formerly separate radial networks, the term “regional rail” began to be used to refer to commuter rail (and sometimes even larger heavy rail and light rail) systems that offer bidirectional all-day service and may provide useful connections between suburbs and edge cities, rather than merely transporting workers to a central business district. This is different from the European use of “regional rail”, which generally refers to services midway between commuter rail and intercity rail that are not primarily commuter-oriented.”

        So 1981: SEPTA regional rail connecting two lines (I don’t know how long). 1990s: Cascades starts, calling itself regional rail. 1990s: Sound Transit starts, calling itself regional transit, and Sounder is called regional or commuter rail. So that’s how the confusion started.

      7. How to distinguish Cascades from Coast Starlight?
        I wouldn’t bother using a single term to distinguish them. They are both intercity rail and I can use them to get to the same places in Oregon that I want to go to.
        If I really needed to distinguish them I would be happy to explain that Coast Starlight goes all the way to California, but I don’t consider them to be all that different.

      8. Cascades (and other services such as the San Joaquins and Surfliner (California), the Wolverine (Michigan), and others) are state supported services.

        The National Amtrak system might not necessarily stop at all the same stops. (i.e. the Coast Starlight does not stop at the Tukwila or Oregon City stations).

        Also, almost all the routes outside of the NEC are only Daily (or less in the case of the Cardinal and the Sunset Limited), whereas the states can schedule more trains in their regional framework.

        For the most part, the national Amtrak system can be defined by the fact they include sleeper accommodations, and the regional services do not.

  3. I call it “commuter rail” and I think I’ve only seen it called “commuter rail”.

    The first aspect of terminological debates is that being able to communicate is at least as important as some sort of ontological optimality. At work we have this thing whose name isn’t immediately obvious from its function, but at some point in the past, somebody gave it the name, so we keep using it because its easier to just tell new people to use the name instead of brainstorming a theoretically better name and trying to get everyone to switch to the new name. Likewise, Metra (in Chicagoland) is often also called “commuter rail” even though it differs from Sounder in some important respects (more frequent service, more city to suburb service, closer stop spacing), but they’re similar enough to lump together. If your first encounter with “commuter rail” was Metra, you’re probably a bit disappointed by Sounder service, but if you’re told that Sounder is “commuter rail” you have a reasonably accurate idea of what it is.

    Secondly, there’s no point in having a terminological debate unless you’re guided by the purpose of using the terminology. At least locally, probably the most important distinction is between Sounder and Link. They might someday both run from Tacoma to Everett, and Sounder might someday have somewhat higher frequencies, but even then, Link will have closer stop spacing, much more frequent service, so people will use it for a greater variety of trips, while Sounder will mostly be used for longer suburb to city trips, many of which will be commuters. So we might as well call Sounder “commuter rail”, while generations of transit nerds can continue to argue endlessly about the distinctions and overlap between “light rail”, “light metro”, and “rapid transit”.

  4. Sounder is commuter rail. I agree with Al S on this.

    As someone that grew up in Germany, the S-Bahn runs all hours of the day albeit with varying frequencies. Sounder does not. When I lived in Germany from the late 80s through 2002, the S-Bahn connected major cities to their suburbs or functioned as a local train between major cities (Mainz-Wiesbaden-Frankfurt). The RER trains are the same.

    1. The RER is also runs frequently enough as to pretty much never need a schedule, even on nights and weekends. Paris also has the Transilien, a more typical commuter rail network.

  5. There is not a single word I know that describes it well other than “commuter”, but it is technically speaking “short-distance locomotive-hauled heavy rail transit”.

    The “short-distance” separates it from “intercity heavy rail” though it does link three “cities”.

  6. Link will function more like an s bahn or suburban rail as it branches out further east, south, and north. Actually given the promised peak frequency on some routes you may be able to describe it as a regional express metro as well.

    Sounder however unless operation patterns evolve, I will always consider commuter rail. Despite serving the centers of towns throughout the puget sound region it only runs at peak hours in one direction. This operation pattern fits firmly in the “commuter rail” pattern but if service were to become more like Caltrain 15 min frequency all day service I’d describe that more like S bahn/Suburban/Regional rail because of its more dependable service schedule

    1. Sounder serves some of the city centers, but some others are park and ride lots with little around them. Sadly, this even includes the two largest suburbs served: Tacoma Dome station and Everett are both quite some distance from anything that would generate robust ridership. It’s one of the issues with orienting a service around serving parking lots: there’s nothing there.

  7. Yeah, commuter.

    But to be aspirational regarding increasing the freqency to beyond it’s current commuter hours, I’d say inter-city, and Amtrak is inter-state. Name it what it actually is.

  8. I grew up in Sydney which has several levels of rail:
    – 1. Light rail in the close inner suburbs (2 lines)
    – 2. Metro, automated single-deck trains that travel well into the suburbs maybe 0.75-1 hour on new lines and lines converted from existing former suburban heavy rail lines (1 line)
    – 3. Suburban rail – double-deck electric trains that span the metropolitan area 1-1.5 hours (7 lines)
    – 3.5. Outer suburban – there are some trains that traverse part of the intercity network and part of the suburban network (as limited stops/express) and the downtown stations instead of stopping at the central terminal.
    – 4. Intercity rail – electric trains that travel 2-3 hours out to cities well outside the metro area, and have toilets but no dining facilities (4 lines)
    – 5. Long-distance rail – diesel trains that travel across the state or into neighbouring states up to 10 hours with dining facilities etc.

    #3 and #4 are blurred a bit as there are some intercity trains that traverse less of the intercity network and more of the suburban network (as limited stops/express) and the downtown stations instead of stopping at the central terminal. These are referred to as “outer suburban”.

    With the distances of lines, and between stations, Link seems somewhere around #2 and being built out to #3 (in my opinion the light-rail type rolling stock was not a good choice). I’d call it suburban rail.

    Sounder would be somewhere about #3.5 but with fewer stops and many fewer services. It would be qualify as outer-suburban rail.

  9. How does “Regional” imply multiple political entities?

    RER translates as “Regional Express Network” – seems apt to me?

    Calling it “commuter” focuses it on getting to/from a physical workplace on a limited schedule, which is the wrong direction. It needs to be an all-day service to be effective.

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