Density and the transit puzzle

How would you choose a route for a transit line? It's a difficult task, particularly in a region as big as the Twin Cities. Developed land stretches out for miles and miles before finally tapering off into farmland or patches of wilderness. Some parts of the region have natural geographic constraints due to rivers and lakes, while other places get blocked off due to human activity: buildings, highways, and railroad lines to name a few. Opportunities for perfectly straight routes often aren't as common as we wish. Even though the core cities and some older suburbs have substantial chunks of street grids, there are inevitably points where the block size shifts or entire pieces get rotated. In particular, areas near the downtowns of Minneapolis and Saint Paul were set up to follow the riverbanks rather than east-west/north-south lines. Those areas still tend to have small blocks and many opportunities for routing buses or rail vehicles—perhaps too many in some cases.

The street grid itself can be an impediment sometimes, increasing travel distance by nearly 30 percent in the worst case (if a straight line between your origin and destination is angled at 45 degrees against the grid). But still, a dense grid offers lots opportunities for getting between places, and allows for good walkability—it's often not a big deal if a bus or rail line misses pockets of density by a couple of blocks, because they can still be easily accessed on foot. Depending on their shape and size, it's not hard to walk 4-8 blocks on either end of a transit trip—or even double that. But when you go into an area where the grid fades away, it becomes much more critical to precisely locate transit stops and stations at cross streets or other locations (such as near bike/ped pathways) that maximize the number of different ways for people to access stations.



Of course, maps merely showing population density don't tell the whole story. Large chunks of downtown Minneapolis don't have any residents, for instance, but there are skyscrapers rising nearly 60 stories high. Clearly there's something there: office buildings. Some are dedicated to major companies, but the buildings are generally renting out space to many different tenants. Residential buildings are mostly excluded from the core of downtown, which is why some areas can feel dead on weekends and evenings. There are high-rises not too far away, but the daytime population of downtown remains dominated by employees who live somewhere else.

It can also be important to show where the boundaries of each region of population are. In sprawling suburbs, the data you try to use in order to make decisions becomes much more sparse. Individual blocks are larger, sometimes huge. Public streets are few and far between, with individual properties connected and yet separated by private drives and parking lots, and bounded by landscaping features such as ditches, creeks, ponds, bushes, and trees.



So, overlaying employment data can help. Unfortunately, it usually isn't available at very good resolution. For my first and third map in this post, I used Transportation Analysis Zone employment information from the MetroGIS DataFinder service overlaid on top of block-level population data from the U.S. Census Bureau. The second and fourth map only show population data (population count per block as a number, density for the color). All of the maps were created using the open-source tool, QGIS.  The first and third map also include bus lines and proposed transit corridors (LRT for Blue and Green Lines, and BRT for the Red and Orange Lines).

Frustratingly, a number of corridors were not included because of a lack of easily-accessible data. The Gateway Corridor is still being nailed down, and was not represented in the DataFinder shapefiles. Even the Bottineau corridor wasn't included, so I added that. "Arterial BRT" and potential streetcar corridors weren't included either, though I did add station objects along Route 54 which is the highest-frequency limited-stop bus route in the Metro Transit system. Other "HiFrequency" lines are shown solid, because they have stops every 1-2 blocks in most cases. The precise routing and stop locations for planned routes are also in flux, so these maps will need to be revisited.

Each TAZ is usually composed of multiple census blocks, so overlaying the two can have some strange effects (I believe the appearance of heavy density northeast of University and Snelling is largely due to employment at the Griggs-Midway building by Fairview melding into an area that's mostly residential, for instance). There also seems to be missing data in a few cases, particularly on the employment side (the University of Minnesota has a lot of employees, though the East Bank campus is seemingly empty). The maps are not the One True Way to see the world.



Still, it's pretty remarkable that we're currently planning to build LRT out to an area with population dispersed like we see above, and with such a sparse street network, when projects to connect denser areas get discarded or downgraded. The number of people per census block is actually relatively high in Eden Prairie, often measured in the hundreds, but it's difficult to move around in the area because of such a stingy layout of roadways, often lacking sidewalks (this map is at the same scale as the second one in this post which focused on south Minneapolis). Looking at aerial photos, the region seems to be bustling with activity, but a lot of that is due to low-slung office and retail buildings with massive parking lots. All the asphalt makes it look more built-up than it is.

The city also has a big employment base—more people work in Eden Prairie than live there. But despite that large number of workers, the employment density isn't all that high. There may be some missing data from employers who declined to submit per-site numbers, but it appears we'd have a much better return if we looked at improving the situation along the I-494 strip and the France Ave/York Ave corridor in Bloomington, Edina, and Richfield, for instance.

But looking at our existing Hiawatha Line seems to show that rules that you think are important can be broken and still result in something that gets broad appeal: There's very little residential density along the east side of Hiawatha Avenue, because it has been and continues to be used as a freight rail corridor for industry (mostly grain traffic). The airport and Mall of America are also critical to the line's success, but they're in areas which are otherwise pretty empty. The Central Corridor also neighbors large areas without any residential use—though that line tends to skip over the "empty" space while other routes seem to skip the populated areas.

The region is certainly running an interesting set of experiments with these routes, as well as some of the others that I couldn't get to. Which ones will turn out the best?

Japanese Shinkansen documentary

Richard Hammond hosts an episode of Engineering Connections which looks at some of the engineering challenges faced by developers of the Japanese Shinkansen high-speed rail system.

Amtrak versus the shutdown

A rail crew replaces a switch on October 4th in preparation for reconnecting the Saint Paul Union Depot to allow Amtrak service.

Amtrak, the National Passenger Railroad Corporation, could cease to be a "national" network if the federal government shutdown drags on. The company has said that it can ride out a short-term shutdown, on the order of "several weeks", but it's unclear what might happen beyond that point. The good news is that the company is in better financial health than they have been in a decade or more, somewhat extending the window of time they can operate without federal assistance. The bad news is that it would still be a extremely difficult task to find the $100 million or so per month they would need to keep running the company as it is today.

The federal shutdown has also come at an impeccably bad time for boosters of the Saint Paul Union Depot project. As you read this, work is progressing on finally connecting the station to mainline tracks in order to allow the Empire Builder to return to a downtown stop it hasn't visited since Amtrak was formed in 1971—the return may only be shortlived.

Of course, political figures have proposed zeroing out Amtrak funding numerous times over the years, or slicing it up into regional businesses, so some thought has been put into how the company might try to cling to life. Until now, at least, the railroad has always received enough support to keep limping along. There have been occasional bursts of greater investment, but never the sustained influx of cash that the company has needed to get a truly stable footing.

Probably the most popular idea has been for Amtrak to condense service down to the Northeast Corridor, the 453-mile D.C.–Philadelphia–New York–Boston line which accounts for more than a third of passenger traffic on the system, and about half of the revenue. That's because there are dozens of trains per day on the NEC, a frequency of service far higher than anywhere else (most of Amtrak's overall route mileage only has one or two trains per direction per day). The NEC is where Amtrak most consistently turns a profit against operating expenses, though that doesn't necessarily cover the costs needed to maintain and upgrade the rails and power systems (for instance, much of the line uses an antiquated 25Hz power supply, unlike the 60Hz power used throughout the rest of the country, and it will cost billions to fix).

Shrinking down to just the NEC, or the NEC plus a few branch routes, probably wouldn't be necessary. Under the Passenger Rail Investment and Improvement Act of 2008, states must take over as primary funders of routes under 750 miles in length. States had until October 1st of this year to negotiate contracts, with October 16th (next Wednesday) set as the service cutoff date. Three states were still in talks at last count. So those routes (roughly 30 across the country) would probably still be able to operate going forward—but those are regional routes which would still become isolated from each other in many cases.

Most at risk are the long-distance trains, such as the Empire Builder which runs through Minnesota. These trains are still mandated under federal law, but don't see any significant financial support from the states that they run through. Would the mandate to keep them running still be valid if the flow of federal money dries up? The long-distance routes are big, meaty targets simply because they are so long. The Empire Builder runs 2,200 miles, not counting the extra split it does near the west coast to serve both Portland and Seattle. In order to maintain daily service, four or five trains need to be in motion on that route at all times, as opposed to a short corridor route of the same frequency which would only need one or two sets of equipment. On the whole, the ticket revenue covers a similar percentage of operating costs on long-distance trains as it does on shorter routes, but shorter corridor trains have a history of needing some amount of state-level funding (which Amtrak counts as "revenue"—something to be wary of if you ever look at their monthly reports).

One possible solution, though it has its limits, is simply raising ticket prices on these routes. Passengers on the Empire Builder paid an average of 18 cents per mile in fiscal 2011, yet the train costs about 35 cents per passenger-mile to operate. Fare increases would be steep, but might barely be able to cover the gap. On the busy Saint Paul to Chicago segment, it's hard to find a regular adult fare any lower than about 32 cents per mile—the fares get much cheaper in the less-populated areas west of the Twin Cities.

Going by that, Amtrak may already run at break-even along the Saint Paul to Chicago corridor, so one alternative could be to truncate the line here. The ridership picture would change drastically, since many people who get on or off within the MSP–CHI corridor are traveling to or from points farther west, but shortening the route would massively improve the on-time reliability of the train, particularly eastbound. The train usually picks up some delay on the way as it plies its way 1,800 miles from the Pacific Northwest to Saint Paul (earning the nickname "Late #8"), and these past couple of years have been particularly bad.

But the Empire Builder is not the most expensive of Amtrak's routes. It has one of the best ratios of ticket revenue to operating cost of the long-distance services, so it may not be the first one cut if things came to that—the Southwest Chief and California Zephyr are both worse in terms of absolute-dollar subsidy. But the Builder isn't far behind on that measure—despite a good operating ratio, the nature of the train and it's long route both contribute to making it one of the most expensive routes to keep running, to the tune of about $57 million per year (the $975 million to be spent on the new Vikings stadium could keep it running for 17 years, or far longer if costs were divided up among states along the route).

Collectively, the long-distance trains need about $600 million per year to keep up with operating expenses. It's not outside the realm of possibility that Amtrak would just start taking out loans to run the services for a while. The company now has its lowest debt load in more than a decade, so that could work for a short- to medium-term period. Of course, that's dependent on credit markets still working properly. With the threat of federal default looming nearby, they could seize up again like in 2008.

What will actually happen? It's hard to say. It probably shouldn't be a top priority as compared to other effects of the shutdown, but it's another thing to keep an eye on as the days turn into weeks. While hoping for the best, transportation officials in states, cities, and counties along long-distance routes should prepare by identifying funds that could be shifted to Amtrak if the need arises.

Bridging highways and rail lines for safety

View Crossings of I-94 vs. ex-NP line in St. Paul in a larger map

The construction of Interstate 94 through St. Paul is often seen as a black mark on the city's history, but there was one fairly positive outcome from the planning processes of the time—there is a very regular interval of pedestrian connections across the freeway, with bridges almost every quarter-mile from the city's downtown to the western border with Minneapolis. Most of the crossings carry a mix of traffic, but some are exclusively built as bike/pedestrian bridges. It's the most consistent stretch of cross-highway connections I've found anywhere in the Twin Cities.

I don't really enjoy crossing I-94 on foot or by bike, but it is easy to find access points. That's in sharp contrast to my own neighborhood about two miles to the north, where there is much poorer connectivity across a railroad line that is more than half a century older than the Interstate. I was starkly reminded of the problem last month when a 9-year-old boy, Marshawn Farr-Robinson, fell from a moving train which chopped his feet off at the ankles. That incident happened at an illegal crossing near Ivy Avenue and Farrington Street (shown with a red marker on my map above).

Minnesota Public Radio reported that the site lacked a required fence, but is sealing up the railroad corridor at this spot really the right response? In order to go the one-block distance from the corner of Farrington and Ivy Ave north to Farrington and Cottage Ave, a person could walk directly across the tracks and get there in about 3 minutes (assuming there wasn't a stopped or moving train blocking the path). Or, that person might decide to take the shortest legal route by going over to Dale Street and doubling back: 7/8ths of a mile, taking about 17 minutes. Even if you had to wait 10 minutes for a train to pass, it'd still be easier to go straight across the tracks, so that's what people do.

I live near an illegal crossing along that same rail line at Hamline Avenue, which people use to get between the Bandana Square area of Energy Park and the Como Park neighborhood just to the north. There's a fence there, but a hole has been cut in it for many years. It periodically gets repaired, but is opened up again just as quickly.

What is the right distance to have between crossings of a man-made or natural boundary—a highway, a rail line, or a river? You can go somewhat overboard, like with the old Milwaukee Road corridor in south Minneapolis, now the Midtown Greenway—that gets up to nearly 16 crossings per mile, or one for nearly every short side of a block. In St. Paul, city blocks are mostly oriented with their long sides running east-west, so the bridges over I-94 are roughly one every two blocks.

We can take a cue from the "desire paths" which cross the railroad tracks today: From visual inspection of the line on the ground and via my favorite mapping sites, it appears that they show up pretty consistently about every 1/2-mile. There are a few oddballs, like a path that has been cut immediately east of Snelling Avenue, but that's partly there because everybody hates using the on-ramps to walk into and out of the Energy Park neighborhood. A spot like Snelling might only need to have some stairways cut into the existing embankments to make a safer crossing, while other places would need bridges or pedestrian underpasses. Those cost a few million dollars each, but with the federal government putting the value of a human life at $7 to $8 million, it's pretty easy to argue in favor of adding new bridges rather than new fences as the best way to make living around railroad lines safer.

The State Fair's missing sidewalks

For Streets.mn's "Our Fair State" series during the Minnesota State Fair, I don't really have a good story to tell about an out-state event. I do, however, live less than a mile from the State Fairgrounds and wanted to share a little of what this heavily pedestrian-oriented event is like to be around the other 353 days of the year.


View Missing Minnesota State Fair sidewalks in a larger map

One of the most surprising things, considering how the fair itself is known for its huge crowds of people doing that seemingly unnatural thing of walking, is that the fairgrounds is missing some sizable chunks of sidewalks around its periphery. Some roads, such as Randall Avenue and Commonwealth Avenue which are on the University of Minnesota Side, aren't major through streets, so may not need sidewalks, but the busy Como Avenue and even busier Snelling Avenue really should see some improvements made.

The missing sidewalk on the north side of Como Avenue between Liggett Street and the University of Minnesota Transitway is mostly just an annoyance since there is still a grassy area to walk on. The lack of a sidewalk on the Snelling Avenue side of the fairgrounds north of Dan Patch Avenue/Midway Parkway is far more dangerous—Snelling Avenue through there is signed at 40 miles per hour, and a lot of traffic goes much faster than that.

Up there, the fence surrounding the fairgrounds directly abuts the roadway near Arlington Avenue, meaning that anyone who attempts to walk along the west side of the road will find themselves walking right in a stream of high-speed traffic. Sadly, there's no real reason to have the fence jut out at that point, other than perhaps to protect a natural gas line. There is enough empty space for a sidewalk along the entire stretch, though retaining the trees and lamp posts may be a challenge. Perhaps an alternative such as hanging plants would be a good alternative to trees in some spots.

When a sidewalk finally does get added on the west side of Snelling, there will still be a problem that Snelling Avenue itself is a busy roadway and hard to cross. But it's possible to take advantage of the fact that northbound traffic can't turn left anywhere between Dan Patch Avenue and Hoyt Avenue and add some pedestrian refuge islands on the south sides of intersections along the road.

Improvements are planned for Snelling Avenue, though a recent intermodal study of the corridor had the northern study area end right at Dan Patch Avenue.  For the Snelling "A Line" enhanced bus service being planned, there is a conspicuously large gap between stations right by the fairgrounds—largely because of the missing sidewalk on the west side.

But for the most part, I've seen the fairgrounds as being a pretty decent part of the neighborhood. After this year, the transit center is moving from its spot on Como Avenue up to the current Heritage Square area. I'm curious what the plans are for the vacated space, since it could be a nice place to develop. Are there any changes you'd like to see around the fairgrounds to make it a better place when the fair isn't going on?

Measure transit quality with your phone

Here are two graphs I made of accelerometer data logged by my smartphone during two different trips I took on Metro Transit lines back in June: One on light rail, and the other on a regular bus. They were just experiments and shouldn't be relied on too much, but they do show that the two types of vehicles are substantially different in the ways they behave.

I've been surprised to have some difficulty finding information about ride quality on mass transit systems, particularly since I find the relative smoothness of the ride to be a compelling argument in favor of rail transit—In my view, ride quality is likely a major contributor to "rail bias." I have to put that in quotes because the implication is that favoritism toward trains, streetcars, and everything in between is based on pure emotion rather than physically-quantifiable factors.

The smartphone revolution (including gadgets like tablets and MP3 players) means that anyone can start gathering data about how good or bad their trip is and start doing some analysis. No longer do you have to wait for a report from some engineering firm contracted out to do the work, or try to sift through dense academic papers. The tool I used to gather data just ended up spitting out raw numbers, so it took a little post-processing to make it a manageable set of data, but it wouldn't be difficult for a smartphone app to be built or extended to directly present users with useful information and comparison points.

Data gathering alone will not end the old bus vs. streetcar vs. whatever else debate, but it's important to bring some real-world measurements into the conversation, since they have been lacking.

For those that are interested, my first graph shows a trip made on the Blue Line (Hiawatha) between Bloomington Central station and Terminal 2–Humphrey station in Bloomington and the MSP Airport area. The second set of data is from a route 3A bus along Como Avenue between about Hamline Avenue and Raymond Avenue. I didn't do anything special to secure my phone in place other than gently holding it down—something that would need to be changed if people try to make repeatable measurements. One document I came across suggested mounting a measuring device on top of a heavy rubber cone placed on the seat—such a cone would dampen some vibrations, but make others more measurable.

Still, with my rudimentary methods, I found it amazing in my graphs to see how much the motion on the 'x' axis (blue, side-to-side motion) went up between taking the train and taking the bus. The the green 'y'-axis plot is for front-to-back motion, while the orange 'z'-axis plot represents up-and-down motion—both of those are harder to interpret visually, though some rudimentary math suggests that y- and z-axis motion is still substantially better than the bus ride. I'll also note that the bus I took the sample on had a very thick cushion on the seat, while the Bombardier LRV I took the light-rail sample on has a very thin seat cushion.

Here are some averages and standard deviations for samples taken along the different axes. I used absolute values when making the averages, otherwise the periodic swinging past the origin line would make the x- and y- numbers very close to zero, and the z-axis average would be very close to 1 (since the z-axis is always being pulled on by Earth's gravity).

LRT	ABS(x)	ABS(y)	ABS(z-1)
Average	0.020	0.045	0.036
Std. Dev.	0.024	0.039	0.047
Bus	ABS(x)	ABS(y)	ABS(z-1)
Average	0.052	0.056	0.042
Std. Dev.	0.048	0.047	0.047

In these two fairly unscientific samples, the bus had average g-loading on the x-axis that was 160% higher than the bus, and it was 24% worse on front-to-back motion, and 17% worse on the z-axis. For me at 220 lbs., the aggregate motion could mean that I'd feel 20 to 40 pounds heavier on the bus than on the train, like I'm swinging around a heavy sack of salt pellets.

But the story isn't all rosy for light rail either—there's a big spike about halfway through my recording, probably due to the train crossing running through a switch, or it may just have been a jerk of my arm as I was holding the phone (perhaps both). Sometime soon I'll have to try this on the Northstar train to see how that one behaves, since it has much more substantial padding on the seats—often making the ride feel smoother—but it also has to share track with heavy freight trains which do a lot of damage to the rails. Hopefully someday we will have some local streetcars to also add into the mix of comparisons.

A rail identity crisis in Minneapolis

View Planned LRT stops in Minneapolis in a larger map

This is what the region's planned light-rail system looks like if you cut it off at the city limits of Minneapolis. It includes the Hiawatha, Central, Southwest, and Bottineau lines. While the first two largely stick to arterial corridors, Southwest (the planned Central/Green Line extension) and Bottineau (the Hiawatha/Blue Line extension) go as quickly as possible to under-populated freight railroad trenches. Again, this is in Minneapolis, where the vast majority of the region's current transit trips begin and end. Something is wrong with this picture.

As of 2013, there are 11 active stations: Ten of them opened in June 2004 when the Hiawatha Line (now Blue Line) started operation, and the eleventh—at Target Field–opened in November 2009 to coincide with the start of the Northstar commuter service. What's really surprising is that, despite the addition of three more routes, the number of stations within the city is only expected to double from 11 to 22: Four have been constructed in Minneapolis for the Green Line (Central Corridor), with probably another five expected to be added for the Southwest extension to Eden Prairie. The Bottineau extension of the Blue Line is only planned to add two stations within the city limits, almost completely bypassing the north side. Looking at these future routes, it almost seems like the Hiawatha Line would have been designed to run out of the city even faster, if not for that pesky Mississippi River in the way.

There are a couple of stops that will be just across the border, of course: Many people would be surprised to discover that the existing VA Medical Center station is just barely outside the city, in the unincorporated territory of Fort Snelling (along with the Fort Snelling stop and the two MSP Airport stops). On the Green Line, the Westgate station is barely past the border—one of the two platforms even extends into Minneapolis by just a few feet. On the planned Bottineau extension, stops at Plymouth Avenue and Golden Valley Boulevard are also just barely outside the city.

It's really remarkable how Minneapolis only gets token access in the Southwest and Bottineau projects. With locally-preferred alignments primarily along freight rail corridors. They are no longer urban transit projects, but are instead commuter or regional services in disguise. And once that fact is acknowledged, it's worth looking at how commuter and regional rail lines are set up elsewhere. In particular, why do we have to with building a double-track light-rail line right next to a freight line when they both have the same 4-foot, 8½-inch gauge? It would arguably be better for the existing freight lines to be upgraded to double-track and run passenger service over that instead of building something totally separate.

There has been some precedent for running light rail on freight tracks: The NCTD Sprinter in San Diego and New Jersey Transit's River Line between Camden and Trenton are two examples. Austin's Capital MetroRail uses essentially the same vehicles as NJT's service, though it is classified as "commuter rail". Those are mostly low-frequency services using significant stretches of single-tracked, non-electrified routes—because it was cheaper to build that way, of course. A closer analog to what's planned for the Twin Cities is likely the UTA TRAX Blue Line in Salt Lake City, which is double-tracked and uses overhead catenary for power.

Frustratingly, the Federal Railroad Administration and Federal Transit Administration have required those lines to use "temporal separation" so that passenger service has exclusive access to tracks during the day, while freight services have exclusive access to track in the overnight hours. The diesel-powered vehicles on the Sprinter, River Line, and MetroRail services are used in Europe on mixed-traffic routes, but somehow we haven't figured out how to do that in the United States because of overblown fears that freight and passenger trains would crash into each other. Even though some services like the River Line have implemented active signaling systems to automatically stop trains before a crash could even happen, the federal government has balked at the idea of having freight service share track with lightweight passenger rail vehicles during daylight hours.

At the other end of the scale, there are some very busy bus corridors in Minneapolis which deserve to be upgraded. Over time, they've been cut out of being potential light-rail lines, though the city is currently pursuing adding streetcar services—something that has caused tension between the city and the Metropolitan Council. Riding the Blue Line down Hiawatha Avenue, it's easy to see why it was derided as a "train to nowhere" ahead of its opening. There are few obvious destinations along the bulk of the route, at least in comparison to historic streetcar corridors like Hennepin Avenue, Nicollet Avenue, Chicago Avenue, University Avenue, and others. The Blue Line does have a massive traffic generator at its southern end with the Mall of America (think of the daily attendance at the Minnesota State Fair, and multiply that by every day of the year), but it's still hard to imagine that rail service along any of those streets would carry any fewer people per mile as the Hiawatha corridor. So are streetcars really the right way to improve service along a busy commercial street which likely has higher inherent transit demand?

The Hiawatha Line blew past ridership expectations when it opened, and now ranks as the 5th-busiest light rail system in the country in terms of boardings per mile. Rather than going "lighter" than "light rail" with streetcars, it seems clear that the true urban corridors in Minneapolis should be getting re-examined for fully grade-separated service like a subway (the "heavy rail" that light rail is "light" in comparison to). That concept was largely discarded in the region many years ago, the argument usually being that "Minneapolis isn't dense enough". Yet the idea hasn't really been revisited even with Hiawatha surpassing ridership levels that weren't expected for another 15 years at least.



Back in the streetcar era, the frequency of service on Nicollet Avenue was every five minutes off-peak and three minutes or less during the busiest parts of the day—it should have been possible to look down the street and see two or three coming your way and a couple of others heading in the opposite direction. Of course, the good thing about sub-3-minute frequencies is that they're showing up all the time, which makes riders happy. But cramming that many rail vehicles onto a surface line mingling with regular traffic means that any disruption can propagate down the line pretty quickly. Each streetcar also needs its own operator, while a longer train can get by with fewer employees per number of passengers.

I'm not sure transit demand is quite high enough that streetcars would go back to historic levels if they were implemented on Nicollet Avenue again, it would probably get pretty close. The Blue Line is running 3-car trains all day long (though they're probably only needed at peak times), so streetcars along Nicollet would have to run three or more times as frequently as Hiawatha's current 10-minute schedule at certain times of day. The frequency can be reduced if multiple streetcars are chained together, but that means larger boarding platforms are needed.

Proper subway lines have higher capacity, faster and more frequent service, and a minimal visual impact on the land above. Longer trains can be used since they don't have to fit between street-level intersections, and the vehicle types can be switched up if the entire route is grade-separated (traditional subway lines allow passengers to walk between cars because the operator cab can be reduced in size—there isn't a need for all-around visibility and there's no risk of crashing into automobiles). Underground trains can operate very frequently and at higher speeds since there isn't cross traffic to worry about—even curves can be eased to allow faster trains, since they don't have to fit past buildings. With rights-of-way reduced or even eliminated, more land is available for developers on the surface, meaning that costs can be offset by very intense transit-oriented development.

Washington, D.C.'s Metro system has really been a poster child for that aspect of building underground. They've also discovered that underground lines stand up better over time since they aren't exposed to weather—a major thing to consider in Minnesota with our heavy use of road salt in the winter. Going underground may also allow the deadlock to be broken between the idea of "railstitution" of busy bus routes with streetcars and the alternate concept of "Arterial BRT" (not technically bus rapid transit since it lacks exclusive lanes, but pulling in every other aspect including better stop spacing, level boarding, and off-board payment).

While the momentum behind existing transit projects in the Twin Cities shouldn't be totally disrupted, it is clear that something has gone wrong with our list of priorities when bridges and tunnels abound on the suburban Southwest LRT corridor, while the far more crowded urban segment along Washington and University Avenues saw tunnels discarded over cost concerns. This isn't just a problem for the Twin Cities region either—many other light-rail corridors across the country have taken the path of least resistance, and ridership has typically suffered because of it. That's not acceptable in a future where people will be asked to live more multi-modal lifestyles.