The Transportation and Mass Transit Megathread

[Bos2Nash]

57 minutes ago, PruneTracy said:

Note also Bos2Nash this is not incompatible at all with a freeway cap, aside from having it bordered by two one-way four-lane roads. Sorry, it's one lane bigger, but it should improve traffic considerably.

Apologies, I didn't mean to say a collector would kill a cap, but rather I did not want more roadway ROW. In all honesty, we already have 3-lane wide roads without any people (aka hippie stuff lol) infrastructure along the edge. So if we are talking about 1 additional lane, but somehow integrating better access management (please no flyover ramps lol) it really isn't that bad and honestly a somewhat reasonable trade off.

1 hour ago, PruneTracy said:

(it would work better if it skipped 12th and started at Division but that's my interpretation of it)

Agreed, but if this would allow for a larger cap, I am not totally against it. Seems like going all the way to 12th could create merge nightmare for folks wanting to be on I-40 and not I-65. Could this be because of a potential height issue at the 12th Ave bridge if things terminated at Division?

1 hour ago, PruneTracy said:

The typical section shows retaining walls between the Interstate and C-D roads and if this were the case it could also be built on a smaller footprint than existing ROW, opening that space for development or other uses.

So are you saying the collector road could also be down in the ROW and could ultimately be capped? Would that not then replace 13th Ave S/George L Davis Blvd and 14th Ave N – or at least allow for possible road diets?

[MLBrumby]

I recall when I was doing an internship in Dallas back in the mid 1990s, central expwy was being completely rebuilt with cantelever access roads along both sides (a Texas thing that works very well) because they could not go any wider with the ROW. The main express lanes  are below grade. Seems that a redo of the loop would need to do that while reducing the merges at the key junctions. I could even see dedicated lanes/ramps from some downtown streets to interstate lanes outside the loop such as demonbreun/division to i-40 east to the airport. That wouldn’t be any good though as things are now along that stretch from the silliman evans bridge to the i24/40 split. Too narrow and too many merges and crossing lanes are done now. 

[PruneTracy]

32 minutes ago, Bos2Nash said:

Apologies, I didn't mean to say a collector would kill a cap, but rather I did not want more roadway ROW. In all honesty, we already have 3-lane wide roads without any people (aka hippie stuff lol) infrastructure along the edge. So if we are talking about 1 additional lane, but somehow integrating better access management (please no flyover ramps lol) it really isn't that bad and honestly a somewhat reasonable trade off.

I think the flyovers are all but necessary at the interchanges given the plan shown. On the north side, for example, it has dedicated ramps to/from both Interstate 40 and Interstate 65. The problem with this is that means one more conflict point in each direction that can't be accommodated in the existing interchange layout, so it will have to go over (or under). The existing overpass for Jefferson Street further complicates things; is the intent for the C-D ramps to overpass Jefferson Street? They should be able to land before they reach Charlotte but would be difficult to get in before the Rosa Parks Boulevard interchange on I-65 or the proposed cap at D. B. Todd on Interstate 40. These issues are also all present on the south side with the additional problem of the 2nd/4th interchange being so close. You could continue the C-D roads to include 2nd/4th and add access to I-65 here but at that point you're just recreating the inner loop traffic patterns on a separate roadway.

32 minutes ago, Bos2Nash said:

Agreed, but if this would allow for a larger cap, I am not totally against it. Seems like going all the way to 12th could create merge nightmare for folks wanting to be on I-40 and not I-65. Could this be because of a potential height issue at the 12th Ave bridge if things terminated at Division?

I meant to say started at Demonbreun. The problem with 12th and Division is mostly on the I-40 westbound / I-65 northbound side; the two overpasses are too close to get a C-D road up or down between them, but are also too close to have two high-capacity signalized intersections. So you can't really start in between them but also don't really want to include both either. It could be done in the eastbound/southbound direction more easily but that would be partial access which the FHWA frowns upon. I'm not sure they would provide that much benefit from the perspective of collecting or distributing traffic relative to the other streets anyway and would probably hack off all the rich yuppies in the Gulch.

32 minutes ago, Bos2Nash said:

So are you saying the collector road could also be down in the ROW and could ultimately be capped? Would that not then replace 13th Ave S/George L Davis Blvd and 14th Ave N – or at least allow for possible road diets?

The C-D roads really need to be surface streets to work effectively. If you're including ramps or similar to move between them and the surface streets, it's similar to what I said before, you're just recreating the inner loop traffic patterns on a separate roadway. That's not to say that they couldn't change grade between intersections, especially with Nashville's topography. But the intent with the bike lanes and sidewalks seems to be to present these as surface streets with frontage for developments in which case they definitely do replace 13th and 14th. It's really not that different than what we have now but would be much cleaner and without the internal weaving/signals from the ramps.

16 minutes ago, MLBrumby said:

I recall when I was doing an internship in Dallas back in the mid 1990s, central expwy was being completely rebuilt with cantelever access roads along both sides (a Texas thing that works very well) because they could not go any wider with the ROW. The main express lanes  are below grade. Seems that a redo of the loop would need to do that while reducing the merges at the key junctions. I could even see dedicated lanes/ramps from some downtown streets to interstate lanes outside the loop such as demonbreun/division to i-40 east to the airport. That wouldn’t be any good though as things are now along that stretch from the silliman evans bridge to the i24/40 split. Too narrow and too many merges and crossing lanes are done now. 

They could do that here and cut the ROW down even further (at the expense of any potential cap) but the main issue (as well as the issue with retaining walls) is maintenance. Much easier and cheaper to work on a series of roads at the ground surface with slopes between them than walls or bridge elements. So if the ROW is existing then I say use it. This is however a potential solution for the east side of the inner loop minus Ellington Parkway which needs to be a full interchange with I-24. Honestly if we nuked the 2nd/4th interchange it would make fixing the problems everywhere else on the inner loop much easier.

[AsianintheNations]

2 hours ago, PruneTracy said:

It's not desirable to extend all the way to the ramp diverge for traffic engineering nerd reasons but your description of the improvements are correct and should help simply from being marked (and having new pavement, as it was people were dodging potholes on the shoulder). Here is a layout of the proposed conditions.

Thanks for all your insights!! And thanks for linking to the actual-to-critical crash rate data visualization. The exit 207-216 stretch with ratio >2.0 is not surprising ... I've started taking Briley the long way around to get to the airport to avoid most of that mess. Presumably the critical crash threshold accounts for volume of traffic, etc. but it would be nice to see the crash numbers in the table normalized to traffic volume or at least to the length of the segment in question. I guess the latter can be approximated by the exit mile markers.

 

[PruneTracy]

36 minutes ago, AsianintheNations said:

Thanks for all your insights!! And thanks for linking to the actual-to-critical crash rate data visualization. The exit 207-216 stretch with ratio >2.0 is not surprising ... I've started taking Briley the long way around to get to the airport to avoid most of that mess. Presumably the critical crash threshold accounts for volume of traffic, etc. but it would be nice to see the crash numbers in the table normalized to traffic volume or at least to the length of the segment in question. I guess the latter can be approximated by the exit mile markers.

 

The crash rate is expressed in crashes per million vehicle-miles traveled, so it accounts for both traffic volume and length of segment, setting aside the normal issues that pop up when quantifying anything in that manner (e.g., arbitrarily short segments can have crash rates approaching infinity). The critical crash rate is more of a statistical function than something that is actually tied to a specific roadway's characteristics; its only inputs are the statewide average crash rate and the segment's exposure rate (the million vehicle-miles traveled number). I forget the statistics terminology but you're just calculating the upper limit of a confidence interval where you can say to a certain p (95%, 99%, etc.) that a segment's crash rate is not attributable to random variation if it is above that limit, i.e., that it has a characteristic that is causing crashes. Of course, if we were being fair, we would calculate the lower limit too and hand out awards to roadway designers if the calculated crash rates were below it, but that approach doesn't get federal funding nor does it cause Phil Williams to come barging into the TDOT commissioner's office.

[smeagolsfree]

Looking at the right of ways available through the downtown loop, TDOT still has room to play with as far as expanding the roadway and I would not be a bit surprised if the made more use of flyovers. I suspect the bridges at Division, Broadway, Church, and maybe 12th will have to be replaced at some point too.

I am not sure when those are due to be replaced either and there needs to be a more efficient system of getting cars on and off the interstate.

[markhollin]

The major intersection involving I-24, Hickory Hollow Parkway, Century Farms Parkway, and William Turner Parkway is now open.

Looking south from Hickory Hollow Parkway, just north of I-24:

Looking north from intersection of Century Farms Parkway and William Turner Parkway:

[MLBrumby]

Some of you may have caught that I love Nashville. but I now absolutely loathe going there. And I may move there someday, if we don't go to Naples. Anyway,  when I can't get out of a trip there I have to leave at the perfect window after Chattanooga's morning rush to even make the trip under 3 hours now, and the return is a crap-shoot.  That covers a lot of issues between Chattanooga and Murfreesboro, and on to Nashville, which is the focus of this topic.  Much of the issues have to do with TDOT's failure to address the incredible growth in traffic along I-24 just in the 15+ years I've lived in Chattanooga.  Don't even get me started on the woeful state of things at the junction of I-24/I59 (technically in Georgia) and eastward through our downtown. For the first time since we moved here, we are getting some Interstate construction but no new lanes (just exit improvements).  Anyway, @Nathan_in_DC's comment about picking up someone at BNA the day before Christmas and how much a transit link to downtown (or wherever) would help matters got me to thinking about this topic.  I first typed this as a reply to that post but realized it was a better fit here.  So here goes... 

Forgive me if this is overly simplistic. I'm not in government and far enough removed from everything the Metro Council does. Something similar may have been laid out previously, but I don't recall seeing it.  I also don't want to be a negative Nancy by echoing Smeags' post from today about Nashville's failure to upgrade infrastructure, but he's absolutely correct. Nothing is as apropos to infrastructure in Nashville as mass transit. The densification of the core cannot continue until this is addressed.

Not as long as there is a lack of leadership on all levels in Nashville will there ever be a sustainable and scalable mass transit system. The desire among the citizenry at large is just not there yet, and it would require a major "sales" pitch. So a strong leader would be needed to sell the idea countywide (and really beyond).  Nashville has suffered from a lack of good leadership on every level of government since Bredesen (maybe Dean) left.  When it takes upward of 30 years to get federal funds for a new and much needed courthouse (nvm how the planning/design/construction was botched from the get-go), there will be slim-to-no federal funds without a solid, sensible transit plan. And this mayor has not shown any inclination to do anything bold. Furthermore, it seems that transit is the third rail that all current Metro politicians fear to touch after what happened to Barry's plan. Hell, TDOT can't even upgrade the expressway system around downtown, much less would they be willing to invest in a transit system unless prodded by a powerful Metro leader(s). Also, as I've mentioned here several times,  proposed transit routes should consider reconnecting streets that were cut-off by Interstate and other development in recent decades. 

I see the pieces required to fall in place (in the following order) ...

1) Mayor proposes a sensible plan that is affordable (and scalable/"phased") and simple enough to communicate to voters (i.e. a subway won't be supported). I'm not sure if the proposed routes are needed at this stage because early negative reactions can kill this effort;

2) Mayor makes pitch to Metro Council with all the benefits to the various districts (e.g. connected streets, sidewalks around stations, traffic management systems in the suburbs, and park/ride stops). IMO this can be abetted by an ad-hoc committee on transit including the WeGo executive(s); 

3) Cost of the system is presented to Council with details and how much in taxes would be required, including state and federal funds. This would require some sharp financial minds in Metro and (likely) consultants (Q: Did the infrastructure bill earmark any funds for new transit systems?);

4) Mayor solicits feedback from Council members as result of community meetings and key businesses (I see Amazon and Oracle among others being ready here);

5) Some tweaking to the plan based on community input and preceived costs/benefits;

6) At some point Metro council would need to gauge what they can authorize with/without a referendum (in the past there have been several oddball 'transit' projects funded with federal grants, eg Clement Landport and/or set up referendum as needed; 

7) Metro Council puts plan up for approval and applying for all federal/state grants/loans/etc. There may even be specific federal grants related to airport transit (IDK) or highway caps or blighted neighborhood assistance... and that's where an effective member of Congress would be very helpful. 

8) Ad-hoc Transit Committee coordinates with TDOT on construction timetable and finalize plans (environmental impact, etc.). 

Maybe some of these tasks could be done simutaneously, but they all would take several years just to complete. And at that point you're only ready to begin the building process.

OK, so pick this apart... PLEASE!  With the power of the minds on this board, maybe someone in Metro government will see this and take the cue.  

[markhollin]

Metro Nashville has put LAZ Parking Georgia LLC — the same firm once at the center of a controversial parking privatization proposal — in charge of its upstart smart parking program.

NDOT Spokesperson Cortnye Stone told the Post that several key details of the contract are still being negotiated but reassured that LAZ was chosen for their approach, experience and qualifications.

"The contract has not yet been negotiated and a contract amount has not yet been set," Stone said. "The values for various components such as capital, operations and management will be determined in the contract negotiation process."

Then-Mayor David Briley sought to give the same company control of Nashville’s parking spaces with the authority to issue tickets and collect fines as well as issue permits for loading zones, street parking and valet parking. The firm’s management of on-street parking came with 2,000 new metered parking spaces at the time.

"Bottom line," Press Secretary Andrea Fanta said, "this is the better deal Mayor Cooper insisted on for taxpayers. We’ll finally modernize our coin-based parking meters and stop leaving millions of dollars on the table. But we won’t sell off the city’s meters, or the public curbside, to do it. The difference here is that Metro, and not a private company, is in control of its own smart parking — and Nashvillians will benefit."

More behind the Nashville Post paywall here:

https://www.nashvillepost.com/politics/metro/metro-awards-smart-parking-contract/article_4403686e-6cd7-11ec-bea5-db1966d0957f.html

[andywildman]

On 1/6/2022 at 3:10 PM, markhollin said:

Metro Nashville has put LAZ Parking Georgia LLC — the same firm once at the center of a controversial parking privatization proposal — in charge of its upstart smart parking program.

NDOT Spokesperson Cortnye Stone told the Post that several key details of the contract are still being negotiated but reassured that LAZ was chosen for their approach, experience and qualifications.

"The contract has not yet been negotiated and a contract amount has not yet been set," Stone said. "The values for various components such as capital, operations and management will be determined in the contract negotiation process."

Then-Mayor David Briley sought to give the same company control of Nashville’s parking spaces with the authority to issue tickets and collect fines as well as issue permits for loading zones, street parking and valet parking. The firm’s management of on-street parking came with 2,000 new metered parking spaces at the time.

"Bottom line," Press Secretary Andrea Fanta said, "this is the better deal Mayor Cooper insisted on for taxpayers. We’ll finally modernize our coin-based parking meters and stop leaving millions of dollars on the table. But we won’t sell off the city’s meters, or the public curbside, to do it. The difference here is that Metro, and not a private company, is in control of its own smart parking — and Nashvillians will benefit."

More behind the Nashville Post paywall here:

https://www.nashvillepost.com/politics/metro/metro-awards-smart-parking-contract/article_4403686e-6cd7-11ec-bea5-db1966d0957f.html

Someone smarter than me can chime in, but I struggle with to balance passing the cost of parking on to the end user (an undisputed good idea) with creating a stronger revenue stream that will ultimately make it harder to kill street parking in the future - whether for bike lanes or transit or wider sidewalks.

[Flatrock]

Wasn't sure where to jam this, so I decided here. Sorry if it's been already posted in another thread. The State of Tennessee has announced yesterday a new license plate design, starting this year. Like it or hate it, it's here.

https://www.tn.gov/revenue/title-and-registration/renewals/coming-soon.html

[markhollin]

Walsh Rd. extension/bridge over Browns Creeks nat Fairgrounds update.

Looking west from Craighead St., 1/2 block north of Seminole Ave:
 

[markhollin]

From NASHtoday:

29. That’s what Nashville scored out of 100 on Walk Score’s walkability meter, making it a “car-dependent” city. 

A walk score is a numeric ranking that represents the walkability of an address based on pedestrian-friendliness and access to businesses. 

Walk Score’s scale of walkability | Screenshot via Walk Score

Points are given based on the distance between residential areas and businesses, including restaurants, retail, and entertainment. Businesses within five minutes (or about a quarter-mile) are given maximum points, with fewer points given to amenities located further away. Anything within a 30+ minute walk is given 0 points. 

Pedestrian-friendliness is calculated by analyzing features of an area’s roads, including the population density, intersection density, and the length of blocks in the area. 

A city’s walkability score is found by calculating the average walkability of many residential addresses in a city. 

Trading in the walking shoes for wheels? Nashville ranks slightly higher forbicyclists with an overall score of 30. 

Walk Score’s scale of bikeability | Screenshot via Walk Score

Don’t let a bad grade get you down. Nashville is already taking steps towards becoming more pedestrian-friendly with initiatives like the WalknBike plan and the proposed River North pedestrian bridge.

In the meantime, here are Nashville’s top five most walkable + bikeable neighborhoods: 

• East Nashville | Walk score: 88 | Bike score: 25
• Downtown | Walk score: 86 | Bike score: 25
• Cameron Trimble | Walk score: 78 | Bike score: 25
• Historic Edgefield | Walk score: 78 | Bike score: 25
• Watkins Park | Walk score: 77 | Bike score: 25

[smeagolsfree]

I am sure if you look at the list, if it were available, most of the cities that rank low are in the south and the west, and the cities ranking high are in the north and east.  Sort of a no brainer. The exception to the list in the south will probably be New Orleans, with cities like Portland ranking higher on the list in the west.

We have to change attitudes towards mass transit and that takes a generation or two to do unfortunately to change a city to a less car dependent city. The other thing that works against Nashville is the fact that this is a city county govt., and the numbers are skewed even worse against it due to its size.

[Mr_Bond]

9 hours ago, smeagolsfree said:

I am sure if you look at the list, if it were available, most of the cities that rank low are in the south and the west, and the cities ranking high are in the north and east.  Sort of a no brainer. The exception to the list in the south will probably be New Orleans, with cities like Portland ranking higher on the list in the west.

We have to change attitudes towards mass transit and that takes a generation or two to do unfortunately to change a city to a less car dependent city. The other thing that works against Nashville is the fact that this is a city county govt., and the numbers are skewed even worse against it due to its size.

If we can get a few neighborhoods with high scores, like East Nashville and Downtown, they will attract the residents that want a higher walk and bike score.  I think the city versus city comparison is silly.  By this measurement, no one lives in the entire city: they live at an address and want to know if they can walk and bike to places.

[smeagolsfree]

14 hours ago, Mr_Bond said:

If we can get a few neighborhoods with high scores, like East Nashville and Downtown, they will attract the residents that want a higher walk and bike score.  I think the city versus city comparison is silly.  By this measurement, no one lives in the entire city: they live at an address and want to know if they can walk and bike to places.

The problem with walking and biking is that it has to be safe! From my experience in the downtown area walking & biking, it is not a safe experience, especially the biking part. I used to bring my bike in and ride downtown but no longer. It's OK on the Greenway I suppose, but to get on regular street and bike is putting your life at risk. I do a lot of walking as you know downtown, and I have to be extremely vigilant as I have almost been hit several times by drivers who run stop signs, red lights, make illegal turns on red, speed, talk on their phones, don't pay attention, or are distracted by the many crazy thing going on downtown. 

As a driver downtown, I have found myself distracted by other things and have almost hit pedestrians because of all the distractions of scooters, trashportaniment, etc., blocking my view. I tend to try and limit my drives and walks now to Sunday mornings.

[Mr_Bond]

57 minutes ago, smeagolsfree said:

The problem with walking and biking is that it has to be safe! From my experience in the downtown area walking & biking, it is not a safe experience, especially the biking part. I used to bring my bike in and ride downtown but no longer. It's OK on the Greenway I suppose, but to get on regular street and bike is putting your life at risk. I do a lot of walking as you know downtown, and I have to be extremely vigilant as I have almost been hit several times by drivers who run stop signs, red lights, make illegal turns on red, speed, talk on their phones, don't pay attention, or are distracted by the many crazy thing going on downtown. 

As a driver downtown, I have found myself distracted by other things and have almost hit pedestrians because of all the distractions of scooters, trashportaniment, etc., blocking my view. I tend to try and limit my drives and walks now to Sunday mornings.

Spot on, Smeags.  It's so easy to be distracted by all the activity.  About three years ago, I almost pressed the gas to turn on to an interstate on ramp and happened to glance up just in time to see two tourists walking in front of my car.  I'll never make that mistake again.  @markhollin, is safety addressed in the study?

[markhollin]

8 minutes ago, Mr_Bond said:

Spot on, Smeags.  It's so easy to be distracted by all the activity.  About three years ago, I almost pressed the gas to turn on to an interstate on ramp and happened to glance up just in time to see two tourists walking in front of my car.  I'll never make that mistake again.  @markhollin, is safety addressed in the study?

All I know about the study is what I posted from NASHtoday.  So I don't think safety was really addressed.  

[colemangaines]

Was daydreaming today about what a rail transit system would look like in Nashville and decided to draw up a map. It includes 4 heavy rail commuter lines and 4 light rail local lines, with the old Landport serving as the hub. This is based on a bunch of impossible/way too optimistic assumptions, like CSX magically disappearing and handing over all the existing rail lines in middle TN. But hey, a guy can dream.

Heavy rail commuter lines (all existing rail)
Yellow line: Gallatin - Hendersonville - East Nashville - Gulch Hub
Red line: Murfreesboro - Smyrna - Antioch - Gulch Hub
Green line: Spring Hill - Franklin - Brentwood - Gulch Hub
White line: Bellevue - White Bridge - Gulch Hub

Light Rail local lines
Blue line: Nashville West shopping center, following Charlotte Ave into downtown, over the HWY 41 bridge, then on to Main St and Gallatin Ave
Teal line: Murfreesboro Pike from Bell Road to the Gulch Hub. Includes BNA terminal connector.
Orange (Broadway) line: Lower Broadway to West End
Purple (Central Loop) line: Loop consisting of existing rail, Charlotte Ave, 4th Ave, KVB, and 8th Ave.

I understand much of this isn't that feasible - for example the purple line taking a right turn from the train tracks onto Charlotte. But I had fun fleshing it out and would like to hear what you guys think.

 

[Luvemtall]

Looks like a plan ! I also daydream a lot about what the future of Nashville can look like. How about using your map and instead of waiting on the impossible with CSX , they just go ahead and build light rail or monorail lines. I really believe that building commuter lines needed to start long ago, and waiting is really not a option. We all know what’s coming down the pike as far as development goes, as long as there’s no major disruption insight it’s just going to keep building. If nothing gets done soon , expect 2-3 hour commute times in the near future. 
PS .. you forgot to assign a color for the one and only existing commuter rail line.. the WEGO STAR , from Lebanon to Downtown. 

[colemangaines]

Well said. Ever since the transit referendum vote it seems like there's been zero dialogue about where to go from here.

And the WeGo STAR omission was halfway on purpose - as far as I can tell, that line ties in with the rest of them down near Radnor Yards at the 65/440 interchange, and it would require a new turning track onto the northbound line. I couldn't think of a great way to go about it so I just left it off.

[bnacincy]

I don't understand CSX's reluctance when it comes to commuter rail in Nashville-it would be a win win for everyone and the trains would only travel on CSX's tracks a couple of times a day-Amtrak runs on CSX tracks in other cities at least that much if not more.

Frustrating.

[rolly]

23 minutes ago, bnacincy said:

I don't understand CSX's reluctance when it comes to commuter rail in Nashville-it would be a win win for everyone and the trains would only travel on CSX's tracks a couple of times a day-Amtrak runs on CSX tracks in other cities at least that much if not more.

Frustrating.

Agreed!

CSX is asshoe

[smeagolsfree]

14 hours ago, bnacincy said:

I don't understand CSX's reluctance when it comes to commuter rail in Nashville-it would be a win win for everyone and the trains would only travel on CSX's tracks a couple of times a day-Amtrak runs on CSX tracks in other cities at least that much if not more.

Frustrating.

I think it has to do with track volume. They have a lot of cargo to be moved through Nashville from my understanding and Rookzie is the master of this, and he knows.

[Baronakim]

One of the things most folks are not seeing about the CSX tracks has nothing to do with sharing the tracks with freight traffic.  That is a non starter in my opinion completely.  However, I have walked the tracks downtown for many years and know that the R.O.W.  is perfectly adequate for additional tracks especially since the switchyard in the Gulch is likely to be closed down to two through tracks.  It would be extremely expensive as far as having to construct new overpasses at major choke points and there is NO solution really for the swing bridge over the river.  However... building a modern railroad beside the  existing low trestles like at 8th and on Gallatin Pike could be built higher and longer span to also eliminate the chokepoints of the automobile traffic as well.  There would have to be some design of switching  for the swing bridge which I do not think is going to  be replaceable (at least without shutting down river traffic  of a height that would  require opening the bridge so a new bridge could be built alongside.  I don't think switching would be a big issue during construction and replacement as the trains cross the existing bridge at very low speeds. This would also be difficult at times of high water too.   This is all IMO physically possible but these upgrades would vastly improve conditions for CSX as well as for commuter rail and highway traffic.  These CSX rail lines through Nashville were first laid before the Civil War.  All of these suggestions are technically similar in scale and costs to the BNA runway built over the highway at Murfresboro Pike.  One thing is clear to me though, if these issues are not addressed and solved now, nothing will change for another century or two.  This would be rather like Nashville's version (in scale of construction) of Boston's "Big Dig" I would think.     It is time to bite the bullet and rebuild it now.

 

Edited January 13, 2022 by Baronakim