Imagine yourself taking a train somewhere, and imagine the train is big and infrequent. Let’s say it’s the commuter train from New York down the Northeast Corridor to Newark Airport, or perhaps a low-cost OuiGo TGV from Lyon to Paris. Now imagine that you change trains to a small, frequent train, like the AirTrain to Newark Airport, or the RER from the OuiGo stop in the suburbs to Paris itself. What do you think happens?
If your guess is “the train I’m connecting to will be overcrowded,” you are correct. Only a minority of a 200 meter long New Jersey Transit train’s ridership unloads at the Newark Airport station, but this minority is substantial enough to overwhelm the connection to the short AirTrain to the terminals. Normally, the AirTrain operates well below capacity. It uses driverless technology to run small vehicles every 3 minutes, which is more than enough for how many people connect between terminals or go to New York by train. But when a big train that runs every 20-30 minutes arrives, a quantity of passengers who would be easily accommodated if they arrived over 20 minutes all make their way to the monorail at once.
In Paris, the situation is similar, but the details differ. Until recently, OuiGo did not serve Paris at the usual terminal of Gare de Lyon but rather at an outlying station near Eurodisney, Marne-la-Vallée-Chessy, ostensibly to save money by avoiding the Gare de Lyon throat, in reality to immiserate passengers who don’t pay full TGV fare. There, passengers would connect from a 400-meter bilevel TGV on which the entire train ridership would get off to a 220-meter bilevel RER train running every 10 minutes. The worst congestion wasn’t even on the RER itself, but at the ticket machines: enough of the thousand passengers did not have Navigo monthly cards for the RER that long lines formed at the ticket machines, adding 20 minutes to the trip. With the RER connection and the line, the trips would be nearly 3.5 hours, 2 spent on the high-speed train and 1.5 at the Paris end.
I even saw something similar in Shanghai in 2009. I visited Jiaxing, an hour away at the time by train, and when I came back, a mass of people without the Shanghai Public Transportation Card overwhelmed the one working Shanghai Metro ticketing machine. There were three machines at the entrance, but two were out of service. With the 20 minutes of standing in line, I would have gotten back to my hotel faster if I’d walked.
This is a serious problem – the ticketing machine lines alone can add 20 minutes to an otherwise 2.5-hour door-to-door trip. To avoid this problem, railroads and transit agencies need a kit with a number of distinct tools, appropriate for different circumstances.
Run trains more frequently
Commuter trains have to run frequently enough to be useful for short-distance trips. If the RER A consistently fills a train every 10 minutes off-peak between Paris and Marne-la-Vallée, New Jersey Transit can consistently fill a local train every 10 minutes off-peak between Manhattan and New Brunswick. Extra frequency induces extra ridership, but fewer people are going to get off at the Newark Airport stop per train if trains run more often. There are some places where adding frequency induces extra ridership proportionately to the extra service, or even more, but they tend to be shorter-range traffic, for example between Newark and Elizabeth or between Newark and New York.
This tool is useful for urban, suburban, and regional service. A train over a 20 kilometer distance can run frequently enough that transfers to more frequent shuttles are not a problem. Even today, this is mostly a problem with airport connectors, because it’s otherwise uncommon for outlying services to run very frequently. The one non-airport example I am familiar with is in Boston on the Mattapan High-Speed Line, a light rail line that runs every 5 minutes, connecting Mattapan with Ashmont, the terminus of the Red Line subway, on a branch that runs every 8-9 minutes at rush hour and every 12-15 off-peak.
In contrast, this tool is less useful for intercity trains. France should be running TGVs more frequently off-peak, but this means every half hour, not every 10 minutes. The only long-distance European corridors that have any business running an intercity train every 10 minutes are Berlin-Hanover(-Dortmund) and Frankfurt-Cologne, and in both cases it comes from interlining many different branches connecting huge metropolitan areas onto a single trunk.
Eliminate unnecessary transfers
The problem only occurs if there is a transfer to begin with. In some cases, it is feasible to eliminate the transfer and offer a direct trip. SNCF has gradually shifted OuiGo traffic from suburban stations like Marne-la-Vallée and Massy to the regular urban terminals; nowadays, five daily OuiGo trains go from Lyon to Gare de Lyon and only two go to Marne-la-Vallée.
Gare de Lyon is few people’s final destination, but at a major urban station with multiple Métro and RER connections, the infrastructure can handle large crowds better. In that case, the transfer isn’t really from an infrequent vehicle, because a TGV, TER, or Transilien train unloads at Gare de Lyon every few minutes at rush hour. The Métro is still more frequent, but at the resolution of a mainline train every 5 minutes versus a Métro Line 1 or 14 train every 1.5 minutes, this is a non-issue: for one, passengers can easily take 5 minutes just to walk from the far end of the train to the concourse, so effectively they arrive at the Métro at a uniform rate rather than in a short burst.
Of note, Shanghai did this before the high-speed trains opened: the trains served Shanghai Railway Station. The capacity problems occurred mostly because two out of three ticketing machines were broken, a problem that plagued the Shanghai Metro in 2009. Perhaps things are better now, a decade of fast economic growth later; they certainly are better in all first-world cities I’ve taken trains in.
Eliminating unnecessary transfers is also relevant to two urban cases mentioned above: airport people movers, and the Mattapan High-Speed Line. Airport connectors are better when people do not need to take a landside people mover but rather can walk directly from the train station to the terminal. Direct service is more convenient in general, but this is especially true of airport connectors. Tourists are less familiar with the city and may be less willing to transfer; all passengers, tourists and locals, are likely to be traveling with luggage. The upshot is that if an airport connector can be done as an extension of a subway, light rail, or regional rail line, it should; positive examples include the Piccadilly line and soon to be Crossrail in London, the RER B in Paris, and the S-Bahn in Zurich.
The Mattapan High-Speed Line’s peculiar situation as an isolated tramway has likewise led to calls for eliminating the forced transfer. Forces at the MBTA that don’t like providing train service have proposed downgrading it to a bus; forces within the region that do have instead proposed making the necessary investments to turn it into an extension of the Red Line.
Simplify transfer interfaces
The capacity problem at the transfer from an infrequent service to a frequent one is not just inside the frequent but small vehicle, but also at the transfer interface. Permitting a gentler interface can go a long way toward solving the problem.
First, tear down the faregates. There should not be fare barriers between different public transport services, especially not ones where congestion at the transfer point can be expected. Even when everything else is done right, people can overwhelm the gates, as at the Newark Airport train station. The lines aren’t long, but they are stressful. Every mistake (say, if my ticket is invalid, or if someone else tries to ask the stressed station agent a question) slows down a large crowd of people.
And second, sell combined tickets. Intercity train tickets in Germany offer the option of bundling a single-ride city ticket at the destination for the usual price; for the benefit of visitors, this should be expanded to include a bundled multi-ride ticket or short-term pass. New Jersey Transit sells through-tickets to the airport that include the AirTrain transfer, and so there is no congestion at the ticketing machines, only at the faregates and on the train itself.
Both of these options require better integration between different service providers. That said, such integration is clearly possible – New Jersey Transit and Port Authority manage it despite having poor fare and schedule integration elsewhere. In France in particular, there exist sociétés de transport functioning like German Verkehrsverbünde in coordinating regional fares; SNCF and RATP have a long history of managing somehow to work together in and around Paris, so combined TGV + RER tickets, ideally with some kind of mechanism to avoid forcing visitors to deal with the cumbersome process of getting a Navigo pass, should not be a problem.