Why Don't We Get Articulated Trainsets?

Paris Articulated TrainTransit systems in the United States have lagged behind in offering trains with connected cars

If you’ve ridden the metro in cities like Paris, Shanghai, or Munich in recent years, you’ll know that they have something no American rapid transit line has on offer: articulated subway trains. Like many shorter light rail trains in the United States, those cities’ newest rolling stock are vehicles that, rather than trains made up of separated cars linked with impermanent connections, are jointed together permanently, allowing passengers to see and walk from one end to the other, usually several hundred feet away.

There are several important advantages of such trainsets. Notably, they increase capacity. Traincars in New York or Washington, for instance, are separated by an unusable gap of up to five feet – a waste of space in those cities’ often cramped trains. Articulated trains, on the other hand, allow passengers to fill those gaps and make them into habitable space, meaning that a typical 8-car train feels more like a less-congested 8-and-1/2-car train when articulated.

Articulation also allows passengers to spread out more evenly throughout the train, because you can get in at one end of the train and walk to the other without leaving.* This prevents the haphazard crowding conditions that sometimes plague subways, in which a car at one end of the train is crowded and a car at the other is completely empty. The hot and empty cars one sometimes sees in the heat of New York summers – where the air conditioning in one car stops working and everyone clears out, making the other cars more crowded – wouldn’t be possible in an articulated trains, where air circulates freely.

So helpful in adding capacity at peak hours, articulation ironically also has the benefit of making empty trains feel safer. By allowing passengers the ability to move between cars easily and to see passengers throughout the train, the isolation that can sometimes feel dangerous on a late-night subway is less of an issue, simply because the whole train is joined together like one huge car.

The obvious benefits of articulation have convinced cities like London and Toronto to order their next rolling stock in similar linked-train formations. What, then, is not to like? Why aren’t we seeing these vehicles being introduced in the United States?

I spoke to representatives of the transit systems in Washington and New York City to ask why their newest trains weren’t articulated and whether any new orders might be designed as such. A WMATA spokeswoman, Lisa Farbstein, told me:

“We have not designed our cars that way. It’s a choice we made when we started the system decades ago. No plans to change it just to change it.”

While I’ll let readers determine whether or not articulation’s sole purpose is “to change it just to change it,” Ms. Farbstein didn’t say much else. She declined to provide any technical reason why Washington was incapable of having articulated cars, which suggests to me that an articulated train such as a customized Bombardier Movia would work fine there. One issue that the spokeswoman declined to bring up was that Washington operates trains of different lengths along its lines; one advantage of working with impermanently connected cars, rather than permanently connected articulated trains, is that you can join together as many cars as you want at a time, rather than having to always run trains at a certain length. As Washington’s network matures, however, one could imagine seeing almost all lines running with eight car trains all the time, something rarely seen on the system today, whose predominant train type is the six-car set.

New York, on the other hand, runs full-length trains on almost all of its lines all of the time (the Brooklyn-Queens Crosstown G is the notable exception). MTA New York City Transit spokesman James Anyansi told me:

“MTA New York City Transit had considered an articulated train which was proposed by Kawasaki under the R110A contract.  The proposal was, however, rejected by us due to the impact it would have had on the project’s budget and schedule… We may take another look at articulated trains in the future if and when we have a budget for Research and Design for an entirely new subway car.”

Though an MTA Metro-North Railroad spokesman told me that articulation would reduce seating and probably not meet FRA structural requirements, there are no such limitations for the city’s subway system according to Mr. Anyansi, and in fact, the city once had articulated cars in operation. The D-Type Triplex trains, manufactured by Pressed Steel, were used on the BMT division of the subway, ran between 1924 and 1965, and featured open connections between groups of three cars. The BMT also experimented over the years with a number of articulated trains constructed in up to five sections, though those projects were abandoned after city unification of the subway network.

It’s disappointing, given this history, to know that we won’t see articulated trains in our cities’ rapid transit networks in the next decade at least (Chicago’s recent order for new trains also did not demand articulation, and fleets in L.A., San Francisco, Philadelphia, Miami, Baltimore, Atlanta, and Boston are not up for fleet replacement at the moment.) But what’s most disappointing is the fact that there’s no technical reason why we can’t have them; rather, it is inertia – “no plans to change it just to change it” – that is holding back our nation’s subway systems from investing in what transit networks in foreign cities all around the world have adopted as the clear new standard.

* Admittedly, it’s possible to do the same on American subways, but that involves opening doors, braving the gap between cars, and usually breaking the rules of the transit system.

Images above: (top) Interior of new Paris Métro MF2000 train (Line 2), from flickr user Meteorry; (bottom) Exterior of Paris Métro MP89 train (Line 1), from flickr user trainmanchuff!

28 Comments | Leave a Reply »
  • Robert Jackel

    While the Articulated idea may be worthwhile in cities like D.C. and New York, it really wouldn’t make sense to spend the money in Philadelphia. The subway very rarely fills up, and at this point doesn’t need that extra capacity.

  • Deacon

    The reason as far as I can tell is, an articulated train set is way lighter than your conventional set. As you know the FRA has the idea that every train on a track in the USA be built like a freight train, because the systems share track and “what if they wreck” OMG its so annoying that nothing here just gets off the ground and common sense prevails. I fully agree with you though.

  • NikolasM

    You could make 4 car train articulated sets in the DC Area. I am fairly certain the end goal there is 8 car trains everywhere (from the current 6), with 4 car trains for off peak times. A 4 car articulated train would certainly be a step in the right direction, but you would lose the option of a 6 car train.

  • 1. Deacan, I doubt articulation would be any lighter than a conventional car. The problem is that FRA mandates end posts and corner posts of several hundred pounds of buff strength. Having passenger accommodation outside the structural integrity of the passenger car would be an invitation to a lot of blood and death in the event of a derailment where cars seperated and accordioned.

    2.This is the reason articulation has not caught on in the US: If one car goes out of service on conventionally coupled cars then you’re down one car. If one car goes down on an articulated set, then the whole train-set is out of service. I’d be interested in hearing the European experience with this issue.

  • Pairs of articulated cars would all 4 / 6 / 8 … in EMU‘s where one car has the power electronics and the other the motors, there’s no way to run odd numbers of cars, and having the ability to swap out one at a time instead of two at a time would be no big deal.

    Of course, if it violates FRA rules for limiting liability to freight operators if a coal train hits a passenger train, without increasing operating or capital costs of coal trains …

    … then that would be limited to rail lines that are not shared with heavy freight and bulk freight traffic.

    Regarding the risk to passengers should the trains separate … permanent couplings make that less likely to happen. Obviously there is a number of units where the reduction in risk exposure by making the event less likely, on the one hand, and increase in risk exposure in the event it happens anyway, on the other hand, would break-even. Somebody would have to do the risk analysis to know whether two, four, or eight car articulated sets net out on the risk reduction side.

  • Having articulated subway cars DO make sense. In addition to the already-mentioned reasons in terms of greater capacity and better ventilation, it has proven that in emergency situations having the ability to navigate from one car to the next without having to slide open doors and get caught in between them/cars is extremely beneficial. Take the London train bombings a few years back. User-taken video showed multitudes of people being able to rush to the exits at the ends of the trains without having to worry about crossing a gap btwn cars…

  • Woody

    When I rode the subway in Santiago, Chile, it had articulated cars and I loved them.

    It is much easier for police (uniformed or undercover) to patrol more than one car at a time when the car ends are wide open.

    In NYC many of the the stations have entrances variously at one end or the other. This feature was designed to reduce crowding on platforms and on trains. So now locals commonly use directions like, “Go to the front end of the train and get off at XYZ Street station.” Of course, you may enter one station at the back end and exit at the front end. So moving from car to car at each stop is something to do if you are in a hurry. With open car ends, there would be no need to pop out onto the platform and dash to the doors on the next car.

    I hate hearing that one reason we can’t have better subway cars, or arrangement of the cars, is because it will be complicated when one fails to operate properly. In this day and age, we should expect subway cars to operate with failures so rare that we don’t need to plan around that likelihood.

  • David Kramer

    I’m pretty sure one big reason is that in many cities with strong labor unions, in mated pairs of individual cars, it makes it easy to have several motormen operating the doors. In a 6 or 8 car articulated set, it would be more obviously superfluous to have a second or even third employee doing a job that the buttons on European metro doors do. Articulation is another one of those design considerations that seem to fall by the wayside along with flush-mounted windows, aerodynamic body designs, and a general sense of “suaveness” that so pervades Asian and European car designs.

  • Deacon, Bruce: FRA regulations apply only to railroads, not to urban transit systems, which are regulated by the Federal Transit Administration. Even FRA-regulated systems, like PATH and the Staten Island Railway, have an out: if they’re completely separated from the freight network, they don’t need to meet crash safety rules.

    David: a New York City Subway train runs with an engineer and a conductor. The conductor is the only one who opens and closes doors and makes announcements, so articulation alone will not make his job superfluous. (The city did in fact try to consolidate the two into one position on one line, without articulation, but the TWU successfully fought it off).

  • NCarlson

    For the record there is some hope in North America, Toronto is getting some articulated trains starting later this year.

  • Tom Rubin

    One of he big objections to articulated trains is that you can’t reduce the trainset during times of lesser demand; you have to run the same size train during off-peak, or even owl service, as you do during weekday peak periods. This, in turn, can lead to running a lot of capacity you don’t really need, or running long trains at very long headways.

    The problem with longer trains than you need is higher operating and maintenance costs. It can cost over $25/hour just for the electricity to operate a single rail car and, of course, the more you run any car, the more maintenance will be needed.

    There are a number of advantages of articulated vehicles. Instead of having a control cab at one end of each vehicle (with married pairs) or two control cabs for each car (light rail), you need two for each train.

    Depending on design, you can save a lot of weight — and moving parts. For heavy rail, rather than having a full two-axle truck at each end of each car, you can have one truck, placed between the “cars,” that supports the ends of the “cars” on each side. This is common with modern HSR trains.

    This is a matter of comparing what you need for each rail line and making the trade-offs — BUT, it can get very difficult to make the conversion from the current single cars or married pairs to full trainsets. This would probably be easiest for a major system like NYCT, where there are several lines that could be changed in total, one at a time — BUT, even that would be a HUGE project, with many major issues.

  • Tom, most lines on NYCT run trains with the same number of cars the entire day. I believe the only exception is the C, plus trains that are reassigned to different lines. However, many trains stay on the same line throughout, including those on the IRT, the L, the J/M/Z, and everywhere else in the system that gets R160s.

  • HGershen

    The author of the article is confusing articulated cars (like most Light Rail where 2 car bodies share one truck; cars on the Stockholm T-Bana are constructed like this) with cars that have permanent, open gangways at the ends but each car body has its own trucks. The Paris Metro illustration is the latter type, also used in Berlin. There really is no good reason why the new NYCTA permanently coupled cars should not have thi design.

  • HGershen -
    The author of this article doesn’t know another word to describe trains with “permanent, open gangways at the ends” other than articulated. The author would encourage you to illuminate.

  • hempro

    Having ridden the Paris “Meteor” line, I can think of two passenger convenience issues.
    1) When the train starts and stops a substantial wind blows back and forth which is annoying as hell, seriously.
    2) There is no way to get away from people with behavioral or odor problems.
    Also, it is fine to fulminate about how this should be a world where things don’t break down and therefore the objections about needing to cut out cars should be moot but, get real.

  • Hempro, do systems that run articulated trainsets, like the Singapore MRT, have problems with cars breaking down?

  • kchamilt

    BART in the S.F. Bay Area has always run ‘articulated’ trains by design since its inception. As the current stock only has the ability to load/unload passengers through a two door per car model (future stock may have three), it really helps that one can move from car to car.
    Also, if a car has its doors locked out, the train operator doesn’t have to interrupt the train’s service just to take that car out of operation. People can still sit in the car, but they would need to enter/exit the car through the end doors.

  • Tom Rubin

    This is a definational thing, but if we are talking about articulation in terms of “unbreakable” trainsets, that’s not BART. If we are talking about the ability to walk from car to car, that HAS been part of BART design — BUT, at the present time, BART does not allow this except in the case of emergencies.

    BART was, to the best of my knowledge, the last U.S. rapid rail system to go with “individual” cars, rather than married pairs. It is, of course, largely because of BART’s experience that the later heavy rail systems went with married pairs.

    Similarly, BART was the last U.S. heavy rail system with two, rather than three, doors, in a now-standard 70/75-foot heavy rail car; again, the rest of the industry learned from BART’s experience.

  • AB

    Just to clarify – NYCT since 2000 has been purchasing cars in 4- or 5-car units (half train length each) that are essentially permanently joined and that have some of the characteristics described above – in particular, there are operating cabs only at each end of each unit, which allows more total usable space per train. Also, NYCT has joined many of its older cars into similar units such that there will be virtually no single cars or even married pairs left by 2010/2011.

    Generally, I believe NYCT has found this to be operationally beneficial – that the benefits outweigh the fact that one problem takes the whole unit out of service (a significant change from NYCT experience in the 1980s, when they purposely bought single cars in order to have maximum flexibility). Significant increases in off-peak ridership have also warranted full-length trains at virtually all times too.

    There is no doubt to me that there would be significant benefits to articulation in terms of passenger circulation and safety. Unlike many newer systems across the world, however, the NYC subway has many and relatively sharp curves, which are responsible for generating at least some opposition to articulation (at least in perception – I don’t know what the actual truth is).

  • Minden-Deutz

    @AB- I believe articulated car sets are actually better at negotiating sharp curves, due to their shorter length than conventional types. Here in Japan the Odakyu Railway uses articulation on its express stock that serves a mountainous area on a sharply curved route.

  • Nathanael

    Chicago still runs trains of substantially varying lengths, and will until nearly all the stations on the system are rebuilt (they just rebuilt the Brown Line stations), so that’s a good reason for Chicago not to use articulated trains.

    Now, Chicago’s platform lengths are all multiples of two cars, so they could have *some* articulation — but there’s a second problem. Chicago has some *intensely* sharp turns on the Loop and a few other places. I question whether any of the standard articulated trains can make those turns.

    The articulated *trams* sold in Europe, with much shorter sections between articulations, could make the turns, but the multiple unit subway stock I’ve seen seems unlikely to manage them. So it would be a custom order. Maybe when they’ve standardized the platform lengths (in, oh, 2050) they’ll do it.

    New York City has less of an excuse, but their response was quite reasonable.

    Washington Metro is currently piecing together trains with bits and pieces of previous orders, and would have to have a second incompatible type of trainset if they ordered artics. That’s not a bad idea, but the response amounts to NYC’s: “When we can afford to design a whole new type of car, we’ll consider it.”

  • Vancouverboy

    Vancouver has articulated systems…. both the older Bombardier built skytrain (fully automated, grade seperated light rail) lines use newer trains that are twin sets of trains… usable in 2 or 4 car formation. On our newest Rotem (subway width/length cars, but shorter stations than larger cities) built line the articulated two car trains can have a middle car added later for a three car articulated formation.
    For the previous questions of what happens when something breaks down.. very simple: Although in all fairness it is quite rare, you just take the articulated couple out… no real harm done with out current 2 or 3 minute headways (line dependent).

  • Max Wyss

    It is a bit an old discussion, but when reading the comments, I have seen an obvious confusion in terminology.

    “Articulated” means that there is an actual articulation joint between the carbodies. In most cases, that articultion joint is supported by a truck (but there are designs where the articulation joiint is free in the air, but a truck just nearby. Such trains are one single unit, consisting of a given number of carbodies, and cabs at their ends. The individual carbodies can not be removed under operational conditions, but only in the workshop, requiring considerable time. The examples in Paris mentioned in the discussion are articulated trains.

    “Married pairs” means that an unit consists of two (or more) carbodies with their own two trucks. In very many cases, a married pair must be considered as one single unit, because one car contains electrical equipment, whereas the other car contains pneumatic equipment, which is shared by both cars. Such units can be separated only in the workshop, but one car can only be replaced by another of the same kind.

    “indidvidual cars” are indeed individual cars which can be combined in specific ways. They may be configured as end cars (motorized or not) or intermediate cars (motorized or not). Depending on their configuration, sets consisting of individual cars can be separated under operational conditions.

    In any cases, in order to change the total train length, only fully self-operational units (with that, I mean units which can operate on their own) can be combined (well, for commuter use anyway; adding “modules” consisting of a cab car and a number of intermediate cars to a push-pull trainset does not really make sense, because in peak times more traction units are needed anyway).

    That said, combining individual cars gives most operational flexibility. However, because such individual units must be self-containing, they are rather heavy, and contain a lot of overhead. An extreme example of this approach would be the US RDCs, which could/can be combined to quite a number of cars. The typical vehicle length is 25 m in this case, and it would allow train lengths in multiples of 25 m

    Married pairs are normally 50 m long, and trains can therefore be multiples of 50 m long. In some cases, a married pair could also consist of three cars, bringing the unit’s length to 75 m.

    Articulated units can be of any length between 50 m and 125 m (or even 200 m). This does indeed reduce the flexibility with train lengths.

    Now, why are articulated units nevertheless appealing? They offer more space for passengers (in the articulation joints). They also offer more space, because shorter carbodies mean that they can be wider and stil match the loading gauge. In addition to that, an articulated unit is much more stable in the case of derailments than individual cars and married pairs. That means that it needs much more to overturn an articulated unit than individual cars, and jackniving is way less likely.In the case a single truck derailing (as it would happen when an axle or wheelset breaks), an articulated unit would stay much better within the loading gauge than individual cars. As we are talking about subways here, which are most likely in tunnels or on viaducts, this can be crucial.

    An articulated unit will also cost less, because for the same length of train, one truck can be spared. A three-unit married pair, being 75 m long has 6 trucks; an articulated unit, 75 m long consisting of four carbodies has 5 trucks.

    The argument about shortening and lengthening a train during the day is valid. However, any such action requires extra staff and most likely extra storage tracks. Also, as capital cost and depreciation are a big part of the operation cost, the savings of not moving a car over keeping it in the consist are minimal, if alone existant.

    Articulated units could indeed be a better choice, particularly when stops are in curves or there are tight curves throughout the network. For DC, the argument may sound silly, but it has some reasons. For New York, one could say that it was a missed opportunity.

  • New York did at one point run articulated trains. Those trains were not fully articulated, but instead had triplets of articulated sections; the total length of each articulated segment was 41 meters.

  • Max Wyss

    Thanks for the link to the New York articulateds, and from there I noticed a few other ones as well; quite interesting, indeed.

    The triplets do definitely make sense, assuming that two of them were the equivalent of 5 “normal” cars.

    It also looked to me as if there were no real gangway through the articulation joint, but then, we have to take into account the year these units were built (roughly around 1930).

    On the other hand, they seemed to be a little bit wider than the standard stock.

    BTW, what I actually wanted to add to my previous comment, but forgot to, is that the famous North Shore Electroliners were articulated trains as well (or am I now totally off?).

  • Drewski

    Toronto gives a good example of why internal circulation can matter on a train. Not only is platform access more restricted in Toronto than in New York or some other cities, but people will cluster at points on a platform or on a train to take advantage of the shortest trip to a connecting bus, streetcar, subway–or the parking lot. It’s bad enough that TTC began crow control techniques, better described as herding. Does it make a difference? Crowd management on platforms on the Yonge line at Bloor cut station dwell times, to the point that the existing signaling system can handle (at its very very best) a 2-minute headway, as opposed to the 2.5 to 3-min headway before crowd management. How do trains change this? You’re already on the train; sometimes, yes, it makes more sense to get out of car 1 and run to car 7 or 8; but sometimes you want to be in car 4,5, or 6 for fastest exit, and you want to be able to move forwards or backwards within the train to make your move. Even in smaller systems, or smaller-scale applications, it makes a difference. Almost all LRT operations involve articulated cars, many of which have a capacity larger than a subway car. A 3-car train on CTrain, San Diego Trolley, or Portland Max still allows a degree of flexibility, which has an impact on the amount of platform space really required. In Cleveland, even a 1-car operation on the Red Line still shows this. Prior to POP fare collection on rail and BRT, it was routine for RTA to restrict access to the door nearest the driver. Didn’t matter if it was a 3-door car–you were gonna board at the front door. So, if you get your happy self up from your seat at the back of the car, and you start walking forward, then you get your happy self positioned for easy access. Movement inside a train of any size is still cheaper than increased investment in station infrastructure, especially when money’s tight.

  • JTD

    The cost to modify the railcar shop that are set up for Married pair (MP) units will be expensive. The jacking system would have to be replaced to handle a train set that is longer than a MP, or a new shop will have to be built.

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