A 100-Year-Old Chicago Transit Line’s Replacement Pondered

» An early scoping report suggests that a subway replacing the Red and Purple Lines in Chicago’s North Side could cost less than an elevated modernization program.

Elevated rapid transit — like any kind of physical infrastructure — degrades over time.

Faced with decades of carrying hundreds of thousands of people daily in a notoriously extreme climate, the rail line that runs local Red and express Purple trains north from Chicago’s Belmont Station to Linden Terminal in Wilmette Evanston along 9.5 miles of track has seen better days. While much of the rest of the elevated and subway system operated by the Chicago Transit Authority (CTA) has been renovated in recent years, this section of rail corridor and the stations associated with it has continued to degrade, resulting in slowed-down, unreliable trains and damaged structural conditions. Of the 21 stations concerned by this corridor, only 6 have handicap access. That’s bad news for the about 125,000 daily users who take advantage of the line every day.

Thus last month the CTA began holding public meetings on what it calls the Red & Purple Modernization Project, an initial step towards the eventual creation of an Environmental Impact Statement, which in turn allows the CTA to apply for federal funds to renovate the corridor.

In this case, there will be no easy options for the city’s transit authority. Certainly nothing will be cheap. But what might be expensive elsewhere — a subway — could turn out to be the most cost-effective solution for Chicago.

In preparation for public events this year, CTA planners have performed simple evaluations on a number of potential options for the corridor, summarized in the chart above.

The CTA has four fundamental options: Maintain the track in its current condition, allowing it to degrade, slowing trains and requiring constant upkeep and high operating costs ($280 million); Rehabilitate the track, putting it into a state of good repair for a short period of time (20 years) and potentially introduce new transfer options from express to local trains ($2.4-2.9 billion); Build a new elevated line along the Chicago section of the corridor, either with three or four tracks, and rebuild the embanked Evanston portion ($4-4.2 billion); and Construct a subway along the southern half of the line, eliminating the existing elevated portions there ($4 billion).

The second pair of options would require removing some existing stations, a possibility that is making some locals nervous already. Some stations on the current line are less than 1,000 feet apart. CTA planners argue that the construction of a new elevated or underground track would reduce travel times and that the insertion of new stations with multiple access points (today most stations only have one entrance) will, on the whole, reduce average walking time to and from transit.

The fact that the subway option may cost about the same as an elevated alternative is a surprise, but these are preliminary alternatives that will be compared in more depth if the CTA finds the funds to advance the study over the next two years. Chicago mayoral race front-runner Rahm Emanuel has suggested that his top transportation priority for the city is to modernize this portion of the Red Line and also extend it south to 130th Street. Even so, neither project currently has any funding specifically devoted to it.

Nevertheless, ridership on this corridor — possibly the densest 10-mile strip in the Midwest — is growing along with a booming residential population. These people need good access to Chicago’s downtown. What choice does the city have but to find the means to pay for the renovation of the line?

Chicago has completed renovations of several of its transit lines in the past, including the Brown Line in 2009, the Dan Ryan stretch of the Red Line in 2007, the Pink Line in 2006, and the South Side Green Line in 1996. Yet the closest comparison to the project may be the renovation of Philadelphia’s Market Street El, which wound up in September 2009. There, the local transit agency spent $740 million effectively turning a 100-year-old, 2-mile line into a brand new two-track corridor, replacing all track, all of the support structures, and all of the stations. At an average cost of $370 million per mile, it is no surprise that Chicago’s planners estimate estimate at least a $4 billion cost ($421 million/mile) for the replacement of their two to four-track line.

Maintaining the status quo or a basic rehabilitation will do little for the city, resolving few of the existing problems and simply postponing needed repairs to a date not so many years off.

Thus a serious, long-term approach to handling the structural conditions of the North Side elevated will require either constructing a new elevated viaduct or building a subway.

From the perspective of maintaining existing operations along the line, the first solution would be extremely difficult since it would require shutdowns of the portions of the line in which the new elevated structure is being built. Chicago rebuilt the South Side Green Line in the early 1990s — by closing it for two years. That is not much of an option along this corridor, where there is no alternative (unlike the South Side, where the Red Line runs just a few blocks from the Green) and where far too many people rely on these rail services to cut them off entirely. It would be extremely expensive from an operations perspective to introduce a bus service capable of carrying hundreds of thousands of people along the corridor, and the result of such a construction period — it could last years — could be thousands of permanently riders lost.

On the other hand, the subway option offers a distinct advantage in this regard because it could theoretically be built even as operations continue on the existing elevated above, much as Boston’s Big Dig added a highway tunnel underneath the city’s downtown expressway, ensuring permanent road access throughout the construction period. That comparison, however, raises the question of whether the underground alternative is really as good of a deal as the planners comparing it to the elevated route seem to make it, since the Big Dig’s cost escalated exponentially over the course of its development.

Moreover, while fewer stops, fewer curves thanks to the new alignment, and more reliable track would speed the underground trains much faster than today’s elevated, the subway would only have two tracks, versus the four now offered. This would eliminate express Purple Line trains between Howard and Belmont Stations — a service that saves commuters almost half their travel time compared to the local Red Line (12 versus 22 minutes) — and require everyone to take the local. On the other hand, all local commuters in the areas now served by both the Purple and Red Lines would then get generally quicker travel times. Planners estimate that this could attract more riders than the other options. Could this be an acceptable trade-off?

The tunneled train alignment does offer one possibility that the city should study very seriously: The option of selling the development rights to the parcels where the elevated trains once ran. Unlike in many places, where elevated trains run directly over a street, on this corridor, the trains run in the middle of blocks. If a subway were built below, a long stretch of real estate would suddenly be available for sale. This could offset construction costs tremendously.

It is sad, perhaps, that Chicago will have to spend so much money on the renovation of an existing line rather than the construction of a new one — if not now, then sometime in the next twenty years. With a large expansion program in the works, the CTA will have to rely on a generous federal commitment to make any of these projects work. In today’s difficult political environment, finding those funds may be difficult.

Image above: Options for CTA North Red and Purple Line Renovation, from CTA