(a note, before we begin: there is definitely a connected theme between my upcoming subway sunday essays, and they serve to make a single, semi-cohesive argument about the state of rail in the new york city area. this post is not part of that, hence the title "aside." i don't currently have any plans for any more of these, but it's entirely possible more ideas will pop up, so here's a... side issue? for the subway sunday saga? anyway. enjoy.)
there are a lot of transit terms that get thrown around these days. "light rail," "heavy rail," "commuter rail," "rapid transit," "metro system"--there are just tons of them, and their definitions all tend to overlap. so here's a glossary/slight ramble (read: eleven hundred words to define five terms) on what all of these commonly used terms mean... or don't mean, or sometimes mean. sigh. let's just get into it.
LIGHT vs. HEAVY RAIL
let's start with light rail, as it's the most unambiguous. wikipedia describes light rail as such:
Light rail transit (LRT) is a form of passenger urban rail transit characterized by a combination of tram and rapid transit features. While its rolling stock is more similar to a traditional tram, it operates at a higher capacity and speed, and often on an exclusive right-of-way. In many cities, light rail transit systems more closely resemble, and are therefore indistinguishable from, traditional underground or at-grade subways and heavy-rail metros.
ok! great! wikipedia is already telling us that light rail is indistinguishable from heavy rail in certain cases. while this is techincally true, we can look to the definition of heavy rail to illustrate a consistent difference. the American Public Transportation Association defines heavy rail as "an electric railway with the capacity to handle a heavy volume of traffic." (emphasis mine.) the volume of traffic is key: light rail systems usually have lower capacities than full-scale heavy rail transit networks.
of course, what defines a "heavy volume" of traffic varies from city to city. in the united states, at the very least, a few additional criteria might be present to help distinguish light rail from heavy rail.
- light rail often has a much lower maximum speed than heavy rail.
- light rail typically has smaller rolling stock (trains) than heavy rail.
- light rail often operates at street level, often next to standard road traffic without any sort of dividing barrier. while these are not guaranteed to be the case with light rail, they serve to further differentiate the category from heavy rail, which defines more robust single-city transit systems, such as the NYC subway or the chicago El.
RAPID TRANSIT, COMMUTER, OR INTER-CITY?
again, let's start with the easiest to define terms first. inter-city rail specifically refers to passenger rail that travels between distinct metropolitan areas. in the united states, this more or less exclusively means amtrak; in other countries, it usually refers to any national or international transit network that exists in that country. where the ambiguity begins, however, is with commuter rail and rapid transit.
let's use wikipedia's definitions again, just so we have a jumping off point:
Rapid transit or mass rapid transit (MRT), also known as heavy rail or metro, is a type of high-capacity public transport generally found in urban areas. A rapid transit system that primarily or traditionally runs below the surface may be called a subway, tube, or underground. Unlike buses or trams, rapid transit systems are railways (usually electric) that operate on an exclusive right-of-way, which cannot be accessed by pedestrians or other vehicles, and which is often grade-separated in tunnels or on elevated railways.
okay, well, shit, there's a word we've already defined. let's look at commuter rail, maybe that'll make things easier:
Commuter rail, or suburban rail, is a passenger rail transport service that primarily operates within a metropolitan area, connecting commuters to a central city from adjacent suburbs or commuter towns. Generally commuter rail systems are considered heavy rail, using electrified or diesel trains. Distance charges or zone pricing may be used.
Generally commuter rail systems are considered heavy rail,
Rapid transit or mass rapid transit (MRT), also known as heavy rail or metro,
:|
alright, so here's the deal. "heavy rail" can mean a lot of things. in the context of metropolitan transit systems, it usually refers to both the size of the operation and the actual size of the train, and so is used pseudo-synechdochally to refer to a rapid transit network as a whole. however, since commuter rail systems also use larger rolling stock and serve greater amounts of people, they count as heavy rail, which makes it very confusing to call rapid transit "heavy rail."
so what've we learned so far? don't use "rapid transit" and "heavy rail" interchangeably. it's confusing.
...anyway. onto the difference between Rapid Transit and Commuter Rail, for real this time.
there are a lot of differences that're usually present: rapid transit systems typically have flat fares while commuter rail has zones, rapid transit typically runs far more frequently than commuter rail, commuter rail almost always operates under the spoke-and hub system1, etc.
however, none of those are actually consistent. each one i mentioned has significant exceptions to the rule across the board: so a different metric is necessary: scale. commuter rail is, generally speaking, intended to serve a whole metropolitan area: the NYC metro as opposed to just the city proper, chicagoland as opposed to just chicago, the bay area as opposed to san francisco--
hey wait a minute.
Bay Area Rapid Transit (BART) is a rapid transit system serving the San Francisco Bay Area in California. BART serves 50 stations along six routes on 131 miles (211 kilometers) of rapid transit lines,
Bay Area RAPID TRANSIT
come the fuck OOOON.
sigh.
ultimately, what is or isn't a rapid transit system is kind of arbitrary. there's definitely a rough vibe and purpose that's mostly distinct from commuter rail, but ultimately it's a spectrum, and any attempt to draw a strict dividing line will result in catastrophe. it's like the gender of trains, i guess.
see you next time for a proper subway sunday post!
1 the model of transit in which various less common destinations are all linked to a central major destination, as opposed to being linked to each other. the T in boston and the El in chicago are run this way... and those are both rapid transit systems. like i say a paragraph later: these are not consistent points with which you can determine which kind of system is which.
