Green Line / Central Corridor construction thread (archive)

[FISHMANPET]

I remember someone saying earlier (maybe even on Minnescraper, and maybe it was mulad) that they're taking their time on the Bridge and not trying to get it done early enough to do a campus stub line. There also wouldn't be rolling stock to pull it off, and even if there was rolling stock there's no room for it at Hiawatha garage, it has to go to lowertown.

[Tcmetro]

All the buses would have to be run from the U to downtown anyways, so there wouldn't be any operational cost savings.

[LRV Op Dude]

by mulad
I don't understand why it's taken all summer either, but they have to keep the track power and signals working on the existing line, for instance

I think you have no understanding of the complexity of the work.

[mulad]

Well, yeah -- I'm a pretty literal guy a lot of the time. When I say, "I don't understand", I often mean to say that there's a gap in my knowledge. I'm always open to learning more about how this stuff works -- I wish it got explained in more detail on a regular basis. I am really glad that the Central Corridor website has as much information as it does -- most transportation projects either don't have websites or only cover the bare minimum -- but it's still only the tip of the iceberg.

Looking around town, there are a bunch of projects that come to mind which have gone fast or have gone slow: The new I-35W bridge was built in a year, while the Wakota Bridge project took 7 years. The Maryland Avenue bridge over I-35E has been built fairly quickly -- assembled offsite and moved into place in the course of a weekend, shaving months off the regular construction schedule. Meanwhile, in my neighborhood, a sidewalk along Lexington Parkway is being converted into a bike path with two new bridges -- that's been taking since last year, despite also having preassembled spans. That seems strange in the context of work the city did last year in replacing a bunch of sidewalks nearby, which typically only took about 3 days each (with many projects running in parallel -- but no bridges, of course).

The Blue/Green interchange project does seem to be moving at a lightning pace compared to the double-crossover next to the TPT building in downtown St. Paul. Complex pieces of track like that are often preassembled and then brought in, but that one has been put together from a couple dozen small pieces of track plus what must be hundreds of other bolts and fittings. On the face of it, it seems silly, though there's probably a reason (such as doing a specialized vibration-mitigation system for the TV studios). But at the same time, we constantly deal with ridiculous transit construction costs in the U.S. -- 2 to 10 times as high as European countries, even adjusted for economic differences. So on one hand, I am definitely open to believing that work goes slowly because it is complex, but on the other hand, I am concerned that things are designed or that work is being done in overly complicated ways just to pull in as much money as possible.

I don't have enough knowledge of the technology in general or these cases in particular to truly pas judgment one way or the other, but I'll continue to yammer on about my sense of things based on what I do know and simply try to be in the ballpark as often as possible.

[Wedgeguy]

by mulad
I don't understand why it's taken all summer either, but they have to keep the track power and signals working on the existing line, for instance

I think you have no understanding of the complexity of the work.

If you notice that some weekend when the Twins are not playing that the section of the Light rail north of the Frankilin station is shut down. This is when they are doing the switch work for the light rail change over to as the stiyches to the Central line. I know this because I live with a light rail operator. There were a minimum of 6 new switches to accomidate the Central line. He has pointed them out to me when we have ridden the rail line together on our way to twins games and back. I believe they are now close to 90% done with the switch work. I'll ask him when I talk with him next. Things are progressing much better than last year as far as I can tell. We do trips along University to check out construction. Not sure how things are going by the Capitol, but I will check that area out tomorrow when I'm in St. Paul for an appointment.

[mulad]

Catenary arms have started to be attached to poles between roughly Raymond Ave and Snelling Ave. Train signal heads have started going in as well.


Image link


Image link

It also looks like curbing has been installed along Washington Avenue almost all the way through the UMN campus, so at least an initial layer of the road surface can't be far behind...

[mulad]

I guess the final weld at the Blue/Green junction happened today. Look at that thermite go!

blue-green-weld.jpg

From the CCLRT Flickr page:

The weld linking the Central Corridor LRT line to the Hiawatha LRT line occurred Sept. 5, 2012, on the flyover or train bridge built over Interstate 35W in Minneapolis between the Cedar-Riverside and Metrodome LRT stations. Miguel Ayala of Herzog Contracting Corp. of St. Joseph, Mo., watches his handiwork.

[UptownSport]

I remember someone saying earlier (maybe even on Minnescraper, and maybe it was mulad) that they're taking their time on the Bridge and not trying to get it done early enough to do a campus stub line. There also wouldn't be rolling stock to pull it off, ...

Guess that kinda eliminates early starts!!
The Washington Ave bridge was an exception, to continue past end of heavy construction, IIRC.
Of course, with my memory ...
It did seem as if bridge was going ahead of schedule.


and thanks, too Mulad- I'd noticed the equipment had moved, but not substantially



All in all, just wishful thinking- Good to see the lines being strung

[FISHMANPET]

I saw that picture and I'm confused, what is that third track for? How could they even be running Hiawatha while they're welding the Hiawatha and Central together?

[mulad]

The third track is for westbound Green Line trains -- it runs parallel to the Hiawatha tracks for a while before merging with them (the eastbound track links up right away). The junction has a lot more in it that what would be strictly necessary -- The simplest option would have only required a single switch for the westbound track and a switch and a diamond (for crossing the northbound Hiawatha track) for the eastbound -- that's basically what was in the Draft Environmental Impact Statement for the Central Corridor, but somebody somewhere didn't like it.

This 2008 report from the Central Corridor website goes into some of the options that they looked at, though it doesn't look like any of them show what has actually been implemented (though the last two are pretty close).

The more complex junction is intended to allow "full bi-directional operation", so that a Hiawatha train could easily turn into a Central train, or vice-versa, without having to go further into downtown Minneapolis (the report said they would have to go all the way to the end of the line at Target Field, but that seems bogus to me). The design also has room for an extra train to park on a "pocket track" without obstructing the normal flow -- that train could then be used for extra service for major events. That pocket track is technically what's in the photo -- there's a double-crossover just to the left of where the photographer was standing, so a westbound Green Line train could move over before reaching that spot. A parked train in that location also has the ability to either run forward into downtown or go in the opposite direction down either the Central or Hiawatha tracks.

The design also appears to add redundancy to the junction -- if one of the normally-used switches fails, there are others in the area that should allow operations to continue with minimal delay by just switching between tracks earlier or later. I'm not sure I would have put so much stuff in this one spot, though -- seems like another option might have been to put crossovers down by the West Bank station, for instance.

Anyway, some of the work has been able to go on while Hiawatha trains have been running, though obviously adding new switches into the Hiawatha tracks means that the track actually has to be cut apart and put back together -- that's why there have been several weekend-long closures this summer where buses carried riders from the Franklin Avenue station into downtown.

[Nick]

The third track is for westbound Green Line trains -- it runs parallel to the Hiawatha tracks for a while before merging with them (the eastbound track links up right away). The junction has a lot more in it that what would be strictly necessary -- The simplest option would have only required a single switch for the westbound track and a switch and a diamond (for crossing the northbound Hiawatha track) for the eastbound -- that's basically what was in the Draft Environmental Impact Statement for the Central Corridor, but somebody somewhere didn't like it.

This 2008 report from the Central Corridor website goes into some of the options that they looked at, though it doesn't look like any of them show what has actually been implemented (though the last two are pretty close).

The more complex junction is intended to allow "full bi-directional operation", so that a Hiawatha train could easily turn into a Central train, or vice-versa, without having to go further into downtown Minneapolis (the report said they would have to go all the way to the end of the line at Target Field, but that seems bogus to me). The design also has room for an extra train to park on a "pocket track" without obstructing the normal flow -- that train could then be used for extra service for major events. That pocket track is technically what's in the photo -- there's a double-crossover just to the left of where the photographer was standing, so a westbound Green Line train could move over before reaching that spot. A parked train in that location also has the ability to either run forward into downtown or go in the opposite direction down either the Central or Hiawatha tracks.

The design also appears to add redundancy to the junction -- if one of the normally-used switches fails, there are others in the area that should allow operations to continue with minimal delay by just switching between tracks earlier or later. I'm not sure I would have put so much stuff in this one spot, though -- seems like another option might have been to put crossovers down by the West Bank station, for instance.

Anyway, some of the work has been able to go on while Hiawatha trains have been running, though obviously adding new switches into the Hiawatha tracks means that the track actually has to be cut apart and put back together -- that's why there have been several weekend-long closures this summer where buses carried riders from the Franklin Avenue station into downtown.

Wow, it almost sounds like someone in Minnesota was thinking ahead when making a billion dollar infrastructure investment...!

[Tcmetro]

Some more updates:

- Track installed from University to Harvard at the U of M.
- Track installed on the curve from the transitway to 29th Av.
- Track installed on Cedar St from 6th to 7th in St Paul.
- Concrete poured on the Cedar St bridge.
- Brick being layed from Harvard to Walnut in the center walkway.
- Cedar still heavily torn up from 7th to 10th. I wonder if this segment will be complete by end of year.

[FISHMANPET]

So wait, does that mean it's possible for a train to go from Cedar Ave station to West Bank station without going into the Downtown East/Metrodome station and then backing out? Or am I misunderstanding that. I suppose if anybody has some pretty pictures of what exactly is going on that would be awesome, but I'm sure I'll find out eventually one way or the other.

[NickP]

Does anyone have any insight on the viability of creating a line from the U to the mall of america without having to transfer at DTE station? I suppose this would bullocks up the scheduling to no end but it would be cool.

[FISHMANPET]

From looking at that PDF mulad posted, it's not possible because there's no track that goes between the West Bank station and the Cedar Ave station, I think they'd need to build another identical junction to make that happen.

As cool as that would be, I don't think there's much benefit. The long term is to run Central and Southwest as one long Green line, and Hiawatha and Bottineua would be the one long blue line. Since both services are fairly frequent, there isn't much of a transfer penalty when going from one to the other.

Here's a piece from Jarrett Walker on why transfers are a good thing:
http://www.humantransit.org/2009/04/why ... -city.html

[Didier]

On my way to Menards last night, I noticed an area right by Vandalia where there is briefly a third track. Does anybody know what the purpose of that is?

[mulad]

There are some crossovers for switching between tracks, but no real third track in that spot.

[Tcmetro]

Some updates:
- University should be opened soon 1 block east of Rice, to Park St.
- Rail was being installed at the Stadium Village and Prospect Park Stations. I wouldn't be surprised if rail is also being installed along the U of M Transitway.
- Curb pouring looks like it will begin soon on the 29th-Emerald and Mackubin-Marion segments. This would leave the major construction left to Cedar St, the Capitol, and the East Bank.

The Aug-Sept newsletter has also been published. The project is 68% complete, and is expected to be 75% complete by year's end:
http://www.metrocouncil.org/transportat ... Sept12.pdf

[mulad]

There is some curved rail at the ends of the transitway segment, but nothing on the straight part yet. Looks like the track here will actually be ballasted rather than embedded in concrete.

[MNdible]

There is some curved rail at the ends of the transitway segment, but nothing on the straight part yet. Looks like the track here will actually be ballasted rather than embedded in concrete.

I suspected as much. Makes sense, as there's no reason to embed in concrete.