Medium Capacity Metro Systems

I was just reading up on Medium Capacity Metro systems, and one column listed capacity per hour as a criteria (20,000-30,000 persons per direction per hour) and it made me wonder how the UTA Trax stacks up. Years ago, a Portland planner explained the virtues of SLC's long blocks--we can run four car trains, when Portland can only run two-car trains. So, how does SLC's capacity stack up?

The Siemens S70 can hold 225 people, at crush loads. SLC can run four cars per train. And I know there are segments of the network that run trains every five minutes (where the blue, red and green lines share track), which is 12 trains per hour.  So: 4*225*12 is 10,880 persons per direction per hour. Which suggests that Trax is not at it's max, it is pretty close to it (10,000-12,000). 12000/4/225 is 13.3 trains per hour, or a train every 4.5 minutes. So Trax is (in certain sections) very close to capacity. And in sections with curves/turns (900 S to 400 S) probably at capacity, and starting to generate delays.

UTA should probably be looking at either an alternate alignment (400 west) through downtown for the green line, or a transit tunnel under the 400 south intersection.   

1970's Rail

There were five Federally funded heavy rail transit systems*** built in the 1970's: MARTA, BART, MetroRail, and the Washington DC METRO

In the history of rapid transit the United States, almost nothing was built between 1928 and the 1970s. (Cleveland's heavy rail the noted exception*). And for good reason--demand for transit collapsed.  But in 1970, we recognized we had 'an urban transportation problem', which is the preferred euphemism for the explosive growth in traffic congestion.

Transit was the clear solution. But even the solution was a problem. Private companies had built most of the transit infrastructure before 1928, and municipalities getting into the game only in response to their failure. But no private entity was willing to build transit in 1970--competition from the automobile was just too fierce. Conservative pundits love to argue that this reflects the innate attractiveness of the automobile. They also love to ignore the billions of dollars in Federal subsidy provided for the Interstate Highway system. So, it order to compete with the automobile, transit projects required a subsidy. Given that the 70's were sort of the high-water mark of 'big government' and centralized planning, it became a Federal project.

None of them did terribly well, at least at first. They had very high costs per rider.** They've done better over time, as traffic congestion has worsened, and developers have responded to the accessibility premium of locations near them, so more things are near them. BART won its spurs when the Bay Bridge collapsed. The DC metro has become the most-ridden transit system in the US.

Many of the characteristics of these systems would carry over into later light rail planning and systems.

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*Planned 1920, partially built 1929-1930, finished 1955-1958.

**For some of the systems, for some years, it would have been better to either a) buy everyone a cheap car, or b) put all of the money into buses.

***DART, despite the similarity of names, is not actually part of the M/ART transit cycle, but part of the 1982+ light rail cycle, starting operation only in 1996. (Initial efforts to fund it began in 1983).

Crossings

Offhand, there are bare handulf ways for a transit line to cross a roadway.

• Grade-separated
• Overpass/viaduct/elevated structure
• Underpass/tunnel/escavation
• Level-crossing
• Time separated
• Railroad Gates
• Traffic Signal

• A metro is a system where both the running way and crossings are grade-separated. 
• A pre-metro is a system (or line) where only the crossings are grade separated. 
• 'Rapid Rail' is the pupae form between metro and pre-metro, where the most urban sections have all their right of way grade separated. The M/ART systems did this.
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Both tend to be heavy rail systems. Or rather, heavy rail systems tend to be either metros. While its well known that 'you can't steer a train', it's less well known 'You can't stop a train' (at least in any reasonable period of time. Ie, if you park a vehicle on the tracks, by the time the driver sees it, it is too late to stop. "With so much steel and steam, I won't slow it down at all". This has been the cause of a number of memorable train crashes, and much conductor trauma. 

And that is the problem with level crossings. Grade-separated crossings remove the 'conflict' between things, with certainty, but are costly to construct. (They have to be able to support a bridge filled with full-loaded semi-trailer trucks, while never exceeding a 5% grade, and being as wide as the roads leading to them). 

Level crossings are much much less safe. Rather than being grade-separated, they are time-separated. When two moving vehicles could be in the same place, this is known as a 'conflict'. When two vehicles attempt to be in the same place, this is known as a 'crash'. Playing 'chicken' with a train ends badly--the train is never going to swerve. Yet drivers managed to run red-lights, and drive around lowered freeway gates with depressing frequency. (It is rare for the driver to survive). 

A Concise History of Rail Transit in America

Modern transit comes from two historic lineages: Steam railroads, and horse-cart street railways. To operate in an urban environment, steam railroads underwent a number of modifications. To reduce conflicts with street level traffic, were either elevated or under-grounded. At some point, they were also electrified, typically use a third-rail system. Once that occurred, expansion required the continued use of grade separated, exclusive guideway, so no one touched the third rail and died. In contrast, street railways were electrified as trolleys, using a pantograph. (Cable-cars can be thought of as a 'dead branch' alternative to electrification). The converging modes of electrified heavy rail and street railways were hybridized as the "Inter-urban". Electrified the whole-way, using a pantograph, and running in a mix of at-grade and tunnels. After the second World War, almost all pure street running 'trolley' systems were 'bus-tituted' out of existence, while some inter-urban systems survived. The survivors all had some off-street running-way, viz: RTA Streetcars, San Francisco cable car, MBTA Green Line & Ashmont–Mattapan High Speed Line, SEPTA Subway–Surface Lines: Suburban Trolley Lines & Girard Ave Trolley, RTA Rapid Transit: Blue and Green Lines, Newark Light Rail, Muni Metro. Between ~1930-1972 is sort of a 'Dark Age' for urban rail--almost nothing new is built. Then there is a resurgence of heavy-rail systems to deal with traffic congestion: BART (1972), Washington Metro (1976), MARTA (1979), Baltimore Subway (1983), and Miami-Dade (1984). All run at-grade in the suburbs, and in tunnels in the city center. About 1980, America adopts the Stadtbahn/'City Rail' concept from Germany, and APTA coins it 'Light Rail'. It runs at-grade in the suburbs, and at-grade in the city-center, like the inter-urbans. Being regulated as 'light' rail, it is allowed to operate in mixed-traffic with cars, making it easier/cheaper to build. Over time, the surviving inter-urbans are rebuilt/revitalized, making use of the same vehicles as the new 'Light Rail' systems. Circa 2001, Portland reinvents the 'streetcar', which runs at-grade, in mixed traffic, with smaller vehicles, and making extensive use of single-track.

Now, to get back to what is 'Rapid' transit: Rapid transit is something that has it's own (unshared) guideway. Subways, elevated rail, commuter rail all clearly meet this standard, as do most of the 'Metro' systems of the 1970's heavy-rail revival. But the surviving inter-urbans and new light rail systems are a confusing mix: They have portions of exclusive guideway, so they have rapid transit portions. But LRT means 'Light Rail Transit' rather than 'Light RAPID Transit'. This gets confusion in the context of BRT, which actually means 'Bus RAPID Transit'. BRT gets developed in Latin America as a sort of bus version of a heavy rail system--buses with unshared guideway. But that's another topic. In summary: HeavyRail = Rapid, Streetcar !=Rapid, LRT !=Rapid...but does have sections that could be. (Cable-cars get lumped in with LRT largely on the basis of Cable-car != heavy-rail.)

And finally: Metro!=Heavy-rail, but Metro ⊂ Heavy-rail. Freight, Metro, Subway, Elevated, Commuter Rail ⊂ Heavy-rail.

=     Equal to
!=    Not equal to
⊂    Is a subset of.