Allen On Travel

A 30 year veteran of world travel (but knows nil about Orlando-area attractions), Will Allen III writes about his weekly odysseys by air on business and how the airlines rob him--and you--of time, the most precious commodity on earth. Time: It's all we have, and the airlines routinely take it from us. This blog challenges the airlines to keep their basic promises.

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Location: Raleigh, North Carolina, United States

Born 1948 in Kinston, NC and raised there in beautiful eastern North Carolina, I now live in Raleigh and commute around the country and the world.

Thursday, February 16, 2012

Passenger Train Lingo Explained,
Part Two

Last week I talked about the two types of intercity passenger trains, regular old Amtrak trains and newfangled high speed rail (called HSR) passenger trains.  In this post I will discuss the types of passenger trains that are used in what's generally called "urban rail transit."

Why the "rail" modifier?  That's to differentiate between everyday rubber-tired city buses that are propelled over concrete and asphalt roadways--buses are the most common type of urban transit vehicles--and steel-wheeled passenger cars (called "vehicles" by transit technocrats) that ride on steel rails (we usually call them "trains"). 

In the world of urban transit, railroads are not called railroads.  They are called a "fixed guideway" mode of transit.  This is because rail passenger cars have to stay on their tracks, unlike buses which can be redirected at will to any halfway decent street or highway.

So what's urban rail transit anyway?  That is, what service need does it fulfill for people who live in cities that provide rail transit?  To understand that, it is useful to consider this chart of the types of local trips we all make every day (with thanks to Reconnecting America):

Keep in mind these are local trips, not trips out of town.  Just the kind of trips we make every day, all day, without much thinking about it.

The first thing I noticed was that only 28% of the trips are for commuting to and from work. That means 72% of our routine trips are not connected to getting to or from our jobs.  It's going to the doctor and dentist and school and shopping and sports events and the grocery store and so on and so forth.  Makes sense when you stop to think about it.

Urban rail transit is divided into two main types, and each type serves a portion of that pie chart of trips we saw above.  One is called Commuter Rail (often abbreviated as "CR"), which mainly provides, as its name implies, a way to get between home and work--the 28% of trips we take every day.  Commuter rail trains usually look a lot like regular old Amtrak trains.

The other is called Light Rail Transit (or "LRT").  LRT serves the 28% of commuter trips as well as the remaining 72% of trips we take.  Light rail takes several forms, but no LRT "mode" (a technocrat's fancy way of saying the type of rail passenger car or train) looks much like a regular old Amtrak train.

Commuter Rail and Light Rail systems complement each other in urban areas large enough and dense enough to support them, with CR handling most of the commuter trips (the 28%) and LRT handling most of the other trips (the 72%).  Both "modes" of urban rail transit are necessary, and both types of rail service must be well-integrated with very frequent and geographically well-distributed bus service that collects and distributes passengers from and to residential areas which are not proximate to CR and LRT stations. 

I mentioned density.  Residential density is important to support an urban rail transit system.  Sprawl = low residential density.  Vast expanses of sprawl around a city are therefore the enemy of successful urban rail transit systems unless the sprawl areas are saturated with well-planned feeder bus service to get passengers to and from stations and unless good park-and-ride lots are provided at both CR and LRT stations. 

However, nosing around the density discussion will soon get you a bloody nose if you aren't careful, because there are lots of nuances. 

Such as a city's geographic distribution of residential areas relative to the location of its urban rail lines.  Even with good feeder bus service serving free shrimp-and-grits and French Champagne on board for breakfast en route to the nearest CR or LRT station, no one is going to travel a big triangular route when they could follow a reasonably straight line by automobile.

Feeder bus service and good park-and-ride lots only work when the urban rail transit system itself is reasonably efficient, i.e., when it takes people from near where they are to near where they need or want to go.

Here are some simple and pretty accurate definitions of CR and LRT adapted from a recent report on transit published by the conservative thinktank, John Locke Foundation:

  • Generally operates on freight rail lines together with freight trains from suburbs to central cities.
  • Is primarily peak period (morning and evening service, with a few midday trains), home-to-work-and-back oriented.
  • Has an average distance between stations of approximately three to five miles and, therefore, tends to have a high speed of operations.
  • Has average passenger trip lengths generally over 20 miles. The Long Island Rail Road and Chicago Metra are examples of commuter rail systems.
  • The specific characteristics of Light Rail Transit (LRT) can vary, but generally operates in short trains, (most commonly, two to three cars) on tracks that may parallel roads, but where rubber tire vehicles (like buses) cannot operate in the same lanes;
  • Have at-grade crossings of streets where the trains, rubber tire vehicles, and pedestrians are separated by signage and signaling;
  • Generally (but not always) are powered by electricity from overhead wires;
  • Have stations at approximately one-mile intervals; and
  • Have speeds and carrying capacities that are lower than that of heavy rail systems (such as the New York City subway system or the Chicago "L," or Washington, DC MetroRail).
  • The Massachusetts Bay Transportation Authority's Green Line in Boston, San Francisco Muni Metro, and Charlotte's LYNX are examples of LRT.
  • Streetcars are considered by the Federal Transit Administration (FTA) to be a subset of LRT, with the main physical differences being the sharing of traffic lanes by streetcars and rubber tire vehicles (buses, cars, and trucks).  Consequently, streetcar operating speed is far lower; smaller streetcar vehicles are common and multiple-car trains are uncommon; there tends to be far more stops; and the routes are generally far shorter than modern light rail lines.

To recap, Commuter Rail trains look a lot like conventional Amtrak trains.  Think Virginia Railway Express (VRE) in northern Virginia or Caltrain in the Bay Area.  They mainly serve people commuting to and from work--the 28% of everyday trips.  CR trains and cars are heavy, which is why they look sort of like Amtrak trains (which are also heavy) and why they can operate side-by-side with freight trains safely (freight trains are real heavy, so passengers trains running on the same tracks as freights need to be just as robust). 

CR trains operate at peak morning and afternoon drive times (commute times) when people are going to and from work, with a few trains running around lunchtime.  CR trains do not usually operate all through the day.  CR stations are normally three to five miles apart.  Commuter Rail stations usually have big park-and-ride lots adjacent to them, and they attract high density residential development close by, and even something called "Transit-Oriented Development" (called TOD), which is a whole 'nother subject.

Light Rail Transit cars, on the other hand, are lightweight and therefore are not allowed to operate side-by-side with freight trains on the same tracks, even though LRT cars ride on the same gauge tracks (that is, four feet, eight and one-half inches between the rails).  

LRT can take many forms, from sleek-looking and fast two- to four-car electric trains running in their own dedicated rail "corridors" (meaning LRT tracks are separate from freight rail tracks) to single car streetcars operating together with rubber-tired vehicles on tracks set into city streets. 

LRT, being light and electric-powered, can accelerate fast and stop fast (unlike heavy CR trains which are slow to get up to speed and slow to stop).  Light Rail Transit trains serve mainly the 72% of trips we take every day other than going to and from work, and therefore LRT trains operate at regular intervals all day long, much like buses. 

LRT tends to attract high density residential development along its route, and especially TOD (mentioned above), because people living within walking distance of LRT stations benefit from the convenient, frequent public transit at their doorstep to take them into the city.

If you read last week's blog post and this one, you are now smart as a whip about passenger train types, and you can argue with the best of them about intercity and urban rail modes!


Blogger Dave said...

I'd be interested on your opinion of the South Shore railway in Northern Indiana (South Bend to Chicago). It has characteristics of both LRT (electrified, and frequent stops), and some of streetcars (it runs at street grade through Michigan City, even making a street-grade stop). It does larger commuter runs, yet has fairly frequent service throughout the day. It seems like a hybrid of LRT and streetcars.


Good article though, and thanks for the explanation!

2/16/2012 8:40 AM  
Blogger hulananni said...

both types of rail service must be well-integrated with very frequent and geographically well-distributed bus service that collects and distributes passengers from and to residential areas which are not proximate to CR and LRT stations.

...and this is not being done on Oahu. I wonder now what will happen to the ugly structures currently being built and the holes in the median where tall palm trees were removed IF rail doesn't go forward after the November election here. There's a good chance of that hpapening! People are fed up with cost overruns and inept management.

2/17/2012 8:40 PM  
Blogger William A. Allen III said...


The South Shore is an electrically powered interurban commuter rail line (as Wikipedia states). It uses heavy-rail cars which run in the same rail "corridor" (meaning on the same tracks) as freight trains. That is different from a Light Rail Transit system which operates in an exclusive rail corridor (that is, no freight trains) and uses much lighter rail cars.

However, since The South Shore trains run all during the day, they do have one of the characteristics of a light rail system. But heavy-rail passenger trains like those on the South Shore, even when electrically powered, just cannot accelerate and slow down as fast as light rail trains. The sheer weight makes it difficult. Therefore, it is difficult to have Commuter Rail stations close together and still achieve reasonable transit times for riders.

Light rail trains, by contrast, are quick to start and stop very fast and can therefore make frequent station stops without losing time.

It's more important when designing a transit system and selecting appropriate rail "mode" types to optimize fulfillment of ridership needs than to worry about whether it's Commuter Rail or Light Rail. Both modes overlap in their service delivery anyway. I tried to keep the descriptions as simply and easy-to-understand as possible rather than to define typologies as having strict and exclusive uses. I apologize if, instead, I confused you. If so, it was an unintended consequence.

2/18/2012 2:41 PM  

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