This is the lead story of the new issue of Works in Progress, Issue 19. Read the full issue, including stories on how to redraw cities and the secret history of inflation targeting, on our website.
In the nineteenth century, the societies of Europe and North America were profoundly transformed by the vast railway networks they built. When these railway networks entered cities, however, they faced a crucial problem: they had to stop. Rather than carrying on through the city, it was common for them to terminate on its edge.
In part, this was due to the high cost of acquiring land in urban areas. It was also a technological problem: the tunneling technologies that would enable railways to run into the centre underground without destroying everything in their path had not yet been invented. Finally, the problem was sometimes regulatory as well: in cities such as London railways were prohibited from penetrating too deep into the urban area.
The result was that nineteenth century railways often terminated roughly wherever the city limits were when they were built. Some Victorian urban networks, like those of London and Paris, thus resemble a vast hubless wheel whose spokes do not quite join one another in the middle. In other cases, the lines circled round the city and then all entered it at the same point, terminating together in one huge station. This model was common in Germany, so that stations of this sort are still sometimes known by the German name Hauptbahnhof (literally: main station).
At the end of the nineteenth century, electrification and improvements in tunneling technology led to the emergence of a new kind of railway: the modern metro. Metros were a huge advance in three ways. First, they could go anywhere in the city. Second, metro lines could easily interconnect with one other, meaning that passengers could use the network to travel swiftly from any part of the city to any other part of the city, rather than merely going from a suburb to the edge of the center. Third, the lines were not bottlenecked by the capacity of a central terminus.
Inner-city termini like London Waterloo and the Gare du Nord in Paris have always handled a complex range of intercity and suburban trains, so delays on any one service can easily propagate over to others. To stop every small delay from generating a huge chain of further delays, tracks and platforms have to be used far below their theoretical maximum capacity: the system can only operate smoothly by preserving a great deal of redundancy. Trains therefore wait around at the terminus for longer than strictly necessary, to recover from delays.
This, in turn, means that termini have to be massive, and in the age of steam, this was compounded by needing to have room to turn around and store steam locomotives and carriages. Today, the Gare du Nord has 28 tracks above ground, and Waterloo has 24.
The giant Gare du Nord (right) and the Gare de l’Est in Paris. Source: Wikimedia Commons .
As demand for railway services grew, these termini filled up. But expanding central termini is rarely straightforward: they are typically surrounded by expensive land containing dense urban fabric which would have to be demolished. Furthermore, they are often located on viaducts or in a trench, which makes their expansion technically difficult. Over time, terminus capacity thus generally became the binding constraint on the number of trains that could be run in and out of the urban core, limiting the frequency of both the suburban trains and intercity services.
Metros, by contrast, could get away with much smaller termini. A typical metro runs a very simple service pattern: every train stops at every station, with few branch lines, and shares no track with any other services, so delays are much less likely. A metro train can easily turn around in well under five minutes, so its terminus only requires two or three platforms.
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