Ottawa Rapid Transit Network developments

[eternallyme]

My opinions on each of them:

In case anyone else might be interested, I thought I'd post the notes I took the other day at the DOTT briefing:

Tunneys Pasture:
- There will be changes in operations to minimize the amount of lay-up space needed
- From the west, every third bus will continue along Scott to Booth and then to Gatineau – not to downtown
- The passenger bridge over the station will need to be widened by about three times to allow the passenger volumes
- Because tired support vehicles can no longer get to the station, it will be covered with a GREEN ROOF
- Although covered, the shelter will not be heated
- The side platforms and the tail tracks are 120 metres each, extending west of Holland Bridge
- Apparently the Holland Bridge is not long enough to allow the trains around a 10 metre central platform
- The underpass from the bus island comes out at track level, so people temporarily cross the tail track
- Trains will alternate between the platforms only during peak periods, otherwise, only one platform is used
- Screen platform doors will add about $1M to each station
- A Tunneys North bus station might be added along the Parkway to ‘spread the pain’

Side platforms are best there due to the station layout, re-using all the existing Transitway infrastructure.

Have they considered your plan to extend it to Westboro at the end of the trench in Phase 1, which would make more sense operationally with little additional cost?

Bayview:
- A new station/bridge to be built north of the existing Transitway Bridge, prolonging bus use
- It will be a tri-level ‘⌐’ station with the O-Train on the west of the bottom level in the interim
- The upper level will be about 3-4 metres above the middle mezzanine, accessed via a bridge from Scott St.
- The upper level has side platforms so the trains are over the columns while the lower has a central platform
- The curves for a converted O-Train going east on the lower level will be protected for
- Prince of Wales Bridge might get ‘wings’ (like the Alexandra Bridge) for STO Rapibus to go to the lower level
- According to the OC Transpo 2010-19 Tactical Plan, Bayview is to be a main transfer hub

I like the wings idea for a temporary bridge, with the ultimate goal being a twinned or reconstructed Prince of Wales Bridge for LRT service to Gatineau.

As for bus use, I don't think Bayview should be a major transfer point, due to the lack of any lay-by area and proximity to downtown. The only bus route which would have to be relocated is the 86, which should run along Booth.

LeBreton:
- Preston will be extended to the Ottawa River Parkway so Booth can be closed during construction
- Booth will get a new 6-lane bridge from Albert to north of the viaduct
- Albert is to be modified to have two left-turn lanes from the west
- LeBreton Station will be about a metre lower than the Transitway, and have a central platform
- Escalators and elevators will extend out from both sides of the bridge to the lower platform

Don't see anything wrong with that plan.

Downtown West:
- The station is under Albert, centered on Bay Street
- There will be a mid-block, south-side access at the new Library and a north-side one at Place de Ville
- Alternately, the easterly access could also be on the south at Constitution Square
- The station platform is to be 30-35 metres below the surface (10-12 stories)
- The tunnel will be concrete lined to minimize water infiltration
- Ventilation will be provided by four shafts, one at each corner of the station
- The renderings show only two UP and two DOWN escalators, one of each at the ends of the central platform
- There will also be two elevators from the platform level plus two staircases

WAY too deep below the surface. I think it should be directly under Slater Street, about 5 storeys below the surface and cut-and-cover from Bay to Elgin.

I'd put it directly under the intersection of Slater and Bay.

All four of the downtown core stations should be central platforms.

Downtown East:
- Stretches roughly between Bank and O’Connor Streets
- Central platform with accesses at Bank, O’Connor at Queen, and perhaps Sparks at O’Connor via a tunnel

I'd shift it to beneath Slater Street between Kent and Bank, with access from the corners.

I'd also add a third station along Slater Street, between Elgin and Metcalfe.

Rideau:
- The station is positioned south of Wellington/Rideau, between Confederation Square and Sussex
- Platform depth near the Rideau Centre is about 27-28 metres – THIS NEEDS TO BE CONFIRMED
- Accesses are planned at the west and east ends, and on the north-east side of the Government Conference Centre

I'd shift it to beneath the Mackenzie King Bridge, either directly below or just to the east of the current bus station (depending on the gradient required below the Rideau Canal). It would require a bored tunnel from just west of Elgin/Slater below the Rideau Canal and on to Campus and Lees Stations.

Accesses should be from the Ottawa Congress Centre, the southeast part of the Rideau Centre and (restricted access) from the DND HQ.

Campus:
- Positioned under the green embankment and Colonel By west of Nicholas
- Probable north access at the Corktown Bridge

I'd keep that plan as is.

Lees:
- Not much changed, it remains as a side-platform station
- Only partially covered and likely only 120 metre platforms at this time
- Sidewalks extend north on both sides of the tracks and cross once the tracks enter the tunnel

I'd continue the tunnel under Highway 417 to Lees Station, building it just east of the current bus station and just beneath the surface, emerging to cross the Rideau River above ground.

I'd add an access directly into the station from the uOttawa campus (former Algonquin Rideau).

Hurdman:
- A side-platform station sitting atop a 4 metre high embankment north of the existing bus station
- There will be two pedestrian passes through the embankment to reach the station escalators/elevators
- HURDMAN STATION DETAILS NEED TO BE CONFIRMED
- Similar to all surface stations, only 120 metre platforms will be built, with 60 expansion space to the east
- The existing bus facilities are to be trashed
- The Nicholas Connector Bridge was not indicated to be a sure thing
- The station is designed to never have the S-E Transitway converted to rail

I'd make drastic changes to Hurdman:

First of all, PROTECT FOR THE SOUTHEAST!!! That is the most important thing IMO, even though it isn't in the best position for train-bus transfers. I'd build it slightly elevated with a central platform (would require a tunnel or an at-grade crossing of the bus loop to connect to the bus platform)

To do so, I'd skew the rail line about 40 degrees, to allow for a reasonable curve in the ultimate stage. The main exit would be at the southeast side to reach the bus platform (which is unchanged), while a second exit at the northwest would reach the bike paths (closed late at night for safety reasons).

Train:
- Much of the central lawn is excavated
- The station extends south-west from the bridge under the east driveway through the bridge on the west driveway
- This is a side-platform station with a bridging walkway along an embankment to the VIA Station entrance
- The $15M Coventry Pedestrian Bridge could be extended to the north-east end of the station

I agree with the proposed plan, it makes the best use of the land and prevents undesirable curves.

St. Laurent:
- The existing upper level is generally unchanged
- The lower level remains side-platform, with the trains separated slightly to avoid a storm sewer in the middle

Best plan IMO, makes costs quite low as the infrastructure is already there.

Cyrville:
- Station stays the same
- Minor track re-alignments stay within the existing property envelope

Don't see any other workable plan. Go with the proposed plan.

Blair:
- Buses will be above the trains
- The lower level will be excavated two metres deeper for the central-platform train station
- Since this will be a terminus for a LONG time, the mall will likely be extended to better integrate with it
- Buses from both the Eastern Transitway and the Cumberland Transitway will transfer passengers here

Bad idea IMO due to the high costs. I would leave the local bus platform alone, and put the trains in the Transitway platform.

In the ultimate stage, the extension to Orleans should go directly under the Blair Road interchange, using underpasses of each ramp (total 4 new bridges) to connect to the existing Transitway.

Rail Yard and Maintenance Facility:
- St. Laurent (between VIA and Belfast) is the recommended location
- The rail cars will be stored indoors

Excellent place, since it is directly adjacent to the St. Laurent Garage and makes good operational sense.

[waterloowarrior]

the sun has another video about the tunnel.. it shows some of the station profiles http://www.ottawasun.com/news/ottawa/200.../news/ottawa/2009/10/23/pf-11508501.html

[Suzie]

Originally Posted by c_speed3108

A station concept

http://www.ottawasun.com/news/ottawa/2009/10/21/11481671.html

It would be more interesting if they did three videos showing how much time it would take a transit user to get from DND Headquarters, Place Bell and L’Esplanade Laurier (these rank among the largest office complexes in Ottawa) to a platform at the nearest station. The videos would be in real-time speed.

The videos could have split screens where the left side would show the tunnel option while the right side would show either the current situation or a surface LRT on Albert Street/Mac Bridge with the same number of stations as the current system.

Such videos would do a good job of illustrating how bad the tunnel option would be for users from a convenience perspective.

[Richard Eade]

Originally Posted by Suzie

It would be more interesting if they did three videos showing how much time it would take a transit user to get from DND Headquarters, Place Bell and L’Esplanade Laurier (these rank among the largest office complexes in Ottawa) to a platform at the nearest station. The videos would be in real-time speed.

The videos could have split screens where the left side would show the tunnel option while the right side would show either the current situation or a surface LRT on Albert Street/Mac Bridge with the same number of stations as the current system.

Such videos would do a good job of illustrating how bad the tunnel option would be for users from a convenience perspective.

Wow, some-one doesn't seem happy about the current plan. It's almost as if you think the $2.1B should give you better service? This is Ottawa. We spend huge sums of money to make things worse.

And to think that roughly $1B would give us a bus tunnel that satisfies the requirement to clear up the congestion and half the job would be done when we do decide that we need to convert to rail.

[rakerman]

A diagram of the old street car network.

http://qshare.queensu.ca/Users01/gordond...l/greber1950/plates_doc/300/plate_14.jpg

[Suzie]

Originally Posted by lrt's friend

Ha, Mercier says "Up to 25 minutes". What crap information. This is like a sale that says 'up to 75% off' when only one item in the store offers this saving. We need to hear average time savings. I believe it will be close to 0 minutes (or even worse) if you fairly include transfer delays and time to use the massive escalators.

I found this on the City’s website http://www.ottawa.ca/residents/public_consult/transit_tunnel/cost_affordability/background_en.html

More efficient travel
Depending on where your trip begins, it is expected that the LRT system will cut 15 to 30 minutes from the time it takes to travel to or from downtown Ottawa. Transit will also be more reliable, as LRT trains will not have to compete with other vehicles for space on our streets.

The claim in the first sentence is absurd. For me, to achieve such savings for most of my trips, the LRT would require negative travel time (for example, my bus trips this weekend between Westboro and Mac Bridge were all below 15 minutes, including one that was only 10 minutes). I would also have to ignore the extra time required to: (1) transfer at Tunney’s Pasture (I am sure that these transfer will be welcomed by all), (2) come up to street level from the deep downtown stations and (3) walk to work from the more distant station.

The transit tactical plan is somewhat more nuanced. Unfortunately, ordinary people interested in this issue are far more likely to read the website backgrounder than to read the tactical plan. In fact, if waterloowarrior had not posted the link, I probably would not have been aware of the plan.

Looking at page 18 of the tactical plan, there are only noticeable savings if you assume a 15-minute congestion penalty for the current system. This is especially true for inside the Greenbelt. Outside the Greenbelt, the plan claims savings of up to 10 minutes even without the congestion penalty. This strongly suggests that the savings are due to what they intend to do to the bus feeder system (fewer but more direct routes). If the bus changes generate such large time savings, why have they not been impletemented yet? Probably because it would lead to user complaints because of the increased walking time (i.e., they would view the changes as making them worse-off).

Pages 17-18 also treats all travel time as equal, which is contrary to empirical evidence. Users regard out-of-vehicle time (walking, waiting and transferring) as much more onerous as in-vehicle time. The tactical plan would result in higher out-of-vehicle time.

[Richard Eade]

Originally Posted by rakerman

A diagram of the old street car network.

http://qshare.queensu.ca/Users01/gordond...l/greber1950/plates_doc/300/plate_14.jpg

Pretty good coverage on that map. And 245 round trips on Bank a day? That's more than 10 trips per hour for each of the 24 hours of the day! Now that's service.

If these services were run by private companies, then they were probably making money; while providing better service than today. Sheesh.

[Suzie]

Originally Posted by O-Town Hockey

As expected, the costs are now up to $2.1B. From the sounds of it, this is not out of keeping with other major infrastructure projects in North America and is well within Ottawa's debt management principles (would incur about $1B debt for the city).

If the increase was expected and is normal for large infrastructure projects (such as tunnels), they should have added an extra contingency (50%-75%) to the original costs estimates. Of course, doing that (i.e., being prudent and honest up-front) could have endangered the project at an early stage.

Hopefully, the 50% increase in costs (with potentially more to come) and the severe financial difficulties being experienced by the province in particular will be enough to convince council to ditch the current plan (which, more than anything, was meant to placate the Albert/Slater Coalition). If we as a City want rail, then put a surface LRT on Albert/Mac Bridge and be more cost-conscientious with respect to the rest of the project. I still doubt that they will make the right decision but I’m more optimistic than I was before. If we need a rail tunnel in 30, 40 or 50 years, we can build it then.

[Suzie]

Originally Posted by Richard Eade

Bayview:
...
- Prince of Wales Bridge might get ‘wings’ (like the Alexandra Bridge) for STO Rapibus to go to the lower level
- According to the OC Transpo 2010-19 Tactical Plan, Bayview is to be a main transfer hub

I'm a bit surprised to see this. I can only presume that this is what the inter-provincial transit study is favouring right now, although I thought it was still early days in that process. It may well be the best option (if the tactical plan is to be believed, this scheme would yield significant savings in operating costs, but also reduce STO ridership by up to 11%). What would be the capital cost of this option? Is it realistic to expect that the the money will be there to do this by 2019?

[adam-machiavelli]

Originally Posted by rakerman

A diagram of the old street car network.

http://qshare.queensu.ca/Users01/gordond...l/greber1950/plates_doc/300/plate_14.jpg

The guy who hosts that image is my master's report advisor.

[lrt's friend]

Originally Posted by Richard Eade

Wow, some-one doesn't seem happy about the current plan. It's almost as if you think the $2.1B should give you better service? This is Ottawa. We spend huge sums of money to make things worse.

And to think that roughly $1B would give us a bus tunnel that satisfies the requirement to clear up the congestion and half the job would be done when we do decide that we need to convert to rail.

Richard, I can't believe what you are saying.

I have been a big critic here, but also a big supporter of LRT in general. I am losing confidence that we are going to deliver a plan that will make transit more attractive.

I have looked at the report and they suggest that my neighbourhood will have 10 to 25 minute faster service. I don't buy this one bit. One the problems has been the speed of service within the neighbourhood itself. You know, circulator routes that they are now advocating even more so in the suburbs. Their solution for our neighbourhood is to create more direct service by simply eliminating service to half our community. I live on a major thoroughfare and service will be eliminated. My 1 minute walk to the bus stop will now be 8 to 10 minutes. For others in my neighbourhood, it will be a 20 to 30 minute walk. How will this result in 10 to 25 minute faster service? It is simply BS.

The service rationalization is occuring in order to pay for LRT and to pay for extending all suburban routes to Baseline, Lincoln Fields and Blair Stations, whereas today they stay within their own communities during off-peak hours. In the case of the southeast, some routes will not be extended to Hurdman, on the theory that the O-Train is good enough. What CRAP! That is only 15 minute service frequency and another transfer at Bayview. Why would I want to use this service unless I absolutely have to?

The bus tunnel concept is sounding more attractive all the time as we only have to pay for the tunnel, we eliminate congestion downtown and Albert and Slater can continue to be used even if the tunnel reaches capacity. Furthermore, the bus tunnel will allow direct services across the city to keep the number of transfers reasonable. Think about it, a bus tunnel results in no need to convert the Transitway to rail, no need to purchase trains, and no need to build elaborate transfer stations at Baseline, Lincoln Fields, Tunney's Pasture, Bayview, Hurdman and Blair. This latter item is really starting to drive up the cost of the project.

The project is now $2.1B and growing and another $1B in Transitway improvements all part of Phase 1 Increment 1 and not open until 2019. That's over $1B commitment we are expecting from the province and the feds. What does it accomplish? It really only heads off a congestion issue. That's why 15 minutes has been added to the time savings. It is not a time savings compared to today in most cases.

It seems to me now that a $1B bus tunnel will be a much more cost effective solution to the downtown congestion issue and it still allows for later installation of trains if necessary, and by then, it will be a true subway.

[eternallyme]

Originally Posted by lrt's friend

Richard, I can't believe what you are saying.

I have been a big critic here, but also a big supporter of LRT in general. I am losing confidence that we are going to deliver a plan that will make transit more attractive.

I have looked at the report and they suggest that my neighbourhood will have 10 to 25 minute faster service. I don't buy this one bit. One the problems has been the speed of service within the neighbourhood itself. You know, circulator routes that they are now advocating even more so in the suburbs. There solution for our neighbourhood is to create more direct service by simply eliminating service to half our community. I live on a major thoroughfare and service will be eliminated. My 1 minute walk to the bus stop will now be 8 to 10 minutes. For others in my neighbourhood, it will be a 20 to 30 minute walk. How will this result in 10 to 25 minute faster service? It is simply BS.

The service rationalization is occuring in order to pay for LRT and to pay for extending all suburban routes to Baseline, Lincoln Fields and Blair Stations, whereas today they stay within their own communities during off-peak hours. In the case of the southeast, some routes will not be extended to Hurdman, on the theory that the O-Train is good enough. What CRAP! That is only 15 minute service frequency and another transfer at Bayview. Why would I want to use this service unless I absolutely have to?

The bus tunnel concept is sounding more attractive all the time as we only have to pay for the tunnel, we eliminate congestion downtown and Albert and Slater can continue to be used even if the tunnel reaches capacity. Furthermore, the bus tunnel will allow direct services across the city to keep the number of transfers reasonable. Think about it, a bus tunnel results in no need to convert the Transitway to rail, no need to purchase trains, and no need to build elaborate transfer stations at Baseline, Lincoln Fields, Tunney's Pasture, Bayview, Hurdman and Blair. This latter item is really starting to drive up the cost of the project.

The project is now $2.1B and growing and another $1B in Transitway improvements all part of Phase 1 Increment 1 and not open until 2019. That's over $1B commitment we are expecting from the province and the feds. What does it accomplish? It really only heads off a congestion issue. That's why 15 minutes has been added to the time savings. It is not a time savings compared to today in most cases.

It seems to me now that a $1B bus tunnel will be a much more cost effective solution to the downtown congestion issue and it still allows for later installation of trains if necessary.

A bus tunnel might indeed work, but it would have to be set up completely for a quick and easy transition to LRT (or even a metro if capacity calls for such).

How much would be saved if the transit tunnel was done through a cut-and-cover tunnel under Slater Street and going beneath the Mackenzie King Bridge?

The Southeast is definitely the biggest flaw in the plan. While it would be unreasonable to build the Southeast LRT immediately, it makes absolutely NO sense that the LRT would have no opportunity to extend southeast from Hurdman on the Southeast Transitway, either requiring an additional transfer, a Y-shaped layout with two separate platforms or skipping Hurdman completely. I would make no significant improvements to the existing O-Train corridor until capacity calls for such, due to the need for an additional transfer and the failure to serve key trip generators (i.e. Billings Bridge, Riverside Hospital, numerous high-density residential areas). I would just leave the existing O-Train alone to serve Confederation Heights and Carleton University, while using the Southeast Transitway as the mainline.

[Franky]

Originally Posted by eternallyme

A bus tunnel might indeed work, but it would have to be set up completely for a quick and easy transition to LRT (or even a metro if capacity calls for such).

How much would be saved if the transit tunnel was done through a cut-and-cover tunnel under Slater Street and going beneath the Mackenzie King Bridge?

The Southeast is definitely the biggest flaw in the plan. While it would be unreasonable to build the Southeast LRT immediately, it makes absolutely NO sense that the LRT would have no opportunity to extend southeast from Hurdman on the Southeast Transitway, either requiring an additional transfer, a Y-shaped layout with two separate platforms or skipping Hurdman completely. I would make no significant improvements to the existing O-Train corridor until capacity calls for such, due to the need for an additional transfer and the failure to serve key trip generators (i.e. Billings Bridge, Riverside Hospital, numerous high-density residential areas). I would just leave the existing O-Train alone to serve Confederation Heights and Carleton University, while using the Southeast Transitway as the mainline.

Would a single 10 m bus tunnel not work? The original plan had two 10 m diameter tunnels, but looking at the Mackenzie King bridge with only 2 lanes working OK even with a stalled bus, I would think a tunnel with 4 lanes at stations and 2 lanes in the tunnel would work OK too and would cost less. It could be converted to easily also.

"5.4.1. Bus-Only Tunnel
Each of the twin tunnels would incorporate a two-lane cross-section comprised of through and passing
lanes within and outside the station areas. This provides an opportunity for buses to pass any disabled
vehicle in the tunnel. Without the passing lane, the tunnel would be blocked until a service vehicle could
remove the bus. This is considered an unacceptable risk, as it would cause a major disruption to rapid
transit operations downtown, and potentially throughout the entire system7. A 10m diameter tunnel bore
will accommodate the two lanes per tunnel, with open-cut techniques used at the tunnel portal locations.
The tunnels would be located sufficiently deep under the street right-of-way to minimize impacts on
existing utilities and avoid disruptions to surface operations during construction.

A centre-island configuration would be used for the station platforms. Advantages of this configuration
include the centralization of passenger amenities, interconnectivity of platforms and shared access facilities
to the surface. For bus technology to take advantage of a centre island platform, a contra flow network is
required. This is accommodated by crossing each tunnel over before reaching the tunnel portal locations. "
- Transportation Infrastructure Requirement Study

[Richard Eade]

Just a quick correction to my previously posted notes: Hurdman is envisioned as a central-platform station - not side-platform as I had previously typed. Sorry for any confusion caused.

[Richard Eade]

We can easily feed over 200 buses per direction through the central Transitway in the morning. This is simply because people exit buses faster than they board them. The only problem in the afternoon is that the dwell time of the buses seems to average about 18-19 seconds because of people needing to pay / show POP when entering the buses. This is rounded up to 20 seconds and gives us the 180 buses per hour. If the stations were 'Fare Paid Zones' then the boarding could be a bit faster. (Still not as fast as exiting due to some 'jockeying for positions', but more buses could be pushed through in the afternoon.)

Now remove any external impedances, such as weather, traffic, signals, pedestrians, etc., and we should be able to push through a few more.

This is what moving all of the buses from Albert and Slater into a tunnel would be like.

But now, let's add a bit of reality: Not every bus will be moved down into the tunnel. Once the train is running, the City's prediction is that the number of buses through the core will drop from 2,600 down to 600 per day. That, apparently, includes STO buses, but assumes that there will be a major transfer station from Rapibus to the train at Bayview. Most of those 600 buses will be OC Transpo buses and most will be during rush-hour.

Let's pick a number like 60 buses remaining on Albert and Slater during the rush-hour only. And let's assume that we can reliably feed 200 buses through our tunnel in each direction.

If we are currently (just) handling the load with 180 buses per hour, then 200 buses gives us more capacity than we need today. Also, if only 120 buses are moved into the tunnel - leaving 60 on the surface - then the tunnel has capacity for another 80 buses! And if that isn't enough, then there is still capacity for 120 on the surface if absolutely needed. (Although this would be a good indicator that it was time to convert to rail.)

OK, a long-winded way of saying that a bus tunnel would definitely work.

Generally when using a Tunnel Boring Machine (TBM), you want an undisturbed tunnel diameter above your tunnel before you get into anything you don't want to affect. Thus, if a 10 metre tunnel were to be bored, then you would want 10 metres left between the top of the tunnel (invert) and the lowest thing above it. If you want to run under a building with a 19m deep foundation, then the tunnel invert will be 29m deep. In the case of a road with buried infrastructure at a depth of 3 metres, then the bottom of your tunnel would be 23m below grade. It might be possible to reduce the depth a bit, but the buffer is a safety thing.

A cut and cover tunnel could be built at a much shallower depth because there is nothing above it that needs to be protected during construction. And the tunnel liner can be constructed to support what-ever needs to be re-built above the tunnel.

For the question of the diameter of a bus tunnel: The 10 metres was chosen to allow separate tunnels, each with two lanes in-case of a break-down. Remember also, that you will loose between 0.5 and 1 metre in diameter due to the liner thickness so a 10 metre tunnel might only give you a 9 metre tube. I would suggest that if the tunnel can be constructed to have a 12 metre finished size, then a centre 'passing-lane' would allow buses to pass obstacles. Of course, the larger the diameter of your TBM, the more muck you need to dispose of. This is where oval TBMs might have an advantage because they can give the required width without the unnecessary extra height.

By the way, I would run the buses in counter-flow directions within the tunnel so that the stations can be central-platform.

I think that the cost of boring a tunnel or building one using cut and cover are close. The bored tunnel should also create less surface disruption. However, if, like Slater, your road is slated to be re-built, then there will be disruption any way. I maintain that the City should have buried empty concrete tubes under Bank since they were digging below all infrastructure and re-laying it. I think the Bank Street work comes in at about $25-30m per year and I’d bet that an extra $100M in each of those years could have done the trick. At the end of this year, we would have had a subway from Wellington to the 417 for about $400M. And they plan to keep going farther south re-building Bank. Maybe we could have had a subway to Lansdowne.

[lrt's friend]

Sounds like a bus tunnel will bring our afternoon capacity to least 380 buses per hour, even more if we leave some STO buses on Wellington.

The Bank Street rebuild tunnel is an interesting idea and it will save money if we plan to build a Bank Street subway, but how can we justify spending $400M for an empty tunnel for an unknown length of time? I have heard of many abandoned incomplete subway projects and this sounds like that may be the outcome. In any event, a Bank Street subway needs to reach Billings Bridge to be truly useful.

[Franky]

Originally Posted by Richard Eade

...

OK, a long-winded way of saying that a bus tunnel would definitely work.

Generally when using a Tunnel Boring Machine (TBM), you want an undisturbed tunnel diameter above your tunnel before you get into anything you don't want to affect. Thus, if a 10 metre tunnel were to be bored, then you would want 10 metres left between the top of the tunnel (invert) and the lowest thing above it. If you want to run under a building with a 19m deep foundation, then the tunnel invert will be 29m deep. In the case of a road with buried infrastructure at a depth of 3 metres, then the bottom of your tunnel would be 23m below grade. It might be possible to reduce the depth a bit, but the buffer is a safety thing.

A cut and cover tunnel could be built at a much shallower depth because there is nothing above it that needs to be protected during construction. And the tunnel liner can be constructed to support what-ever needs to be re-built above the tunnel.

For the question of the diameter of a bus tunnel: The 10 metres was chosen to allow separate tunnels, each with two lanes in-case of a break-down. Remember also, that you will loose between 0.5 and 1 metre in diameter due to the liner thickness so a 10 metre tunnel might only give you a 9 metre tube. I would suggest that if the tunnel can be constructed to have a 12 metre finished size, then a centre 'passing-lane' would allow buses to pass obstacles. Of course, the larger the diameter of your TBM, the more muck you need to dispose of. This is where oval TBMs might have an advantage because they can give the required width without the unnecessary extra height.

By the way, I would run the buses in counter-flow directions within the tunnel so that the stations can be central-platform.

I think that the cost of boring a tunnel or building one using cut and cover are close. The bored tunnel should also create less surface disruption. However, if, like Slater, your road is slated to be re-built, then there will be disruption any way. I maintain that the City should have buried empty concrete tubes under Bank since they were digging below all infrastructure and re-laying it. I think the Bank Street work comes in at about $25-30m per year and I’d bet that an extra $100M in each of those years could have done the trick. At the end of this year, we would have had a subway from Wellington to the 417 for about $400M. And they plan to keep going farther south re-building Bank. Maybe we could have had a subway to Lansdowne.

Cut and cover or New Austrian Tunnelling method (NATM) or oval TBM would move less muck/rock because the shape of the tunnel can be optimized. 2 lanes allows movement by stopping traffic in one direction then the other (like a stop light) which would slow things down but not completely block traffic. If the tunnel is to be upgraded to rail eventually anyway, it may just be an incentive to do it sooner. A passing lane might be used to augment traffic by designating the centre lane to traffic in one direction or the other (assuming asymmetric flow, perhaps from STO buses).

I don't see the big advantage of central-platform with counter-flow buses. Many subway stations don't use central platforms. I wonder what the difference in cost is for a non-central platform. I can't imagine it's very significant when the cost of Boring the tunnel seems to be the major factor. 10% more on $40 million stations is $4 million per station, $12 million on the $500+ million project or about 2.5% (per 10% increase in station cost). Especially in a single tunnel where buses can pass using a centre lane, overtaking when the driver is near the edge and not the middle can be tricky. Visibility is a problem.

[MalcolmTucker]

Re: Central vs side platforms

It is all a matter trade offs cost wise. With side platforms, the only excavation you need wider than the tunnel is the station box, which can allow for narrower tunnels. Central platforms require approaches to widen the distance between the tracks. Since more excavation = more dollars, if the extra amount of excavation costs more than putting in a second elevator and over building stairs/escalators for the side platforms you go with side platforms, and vice versa.

[Kitchissippi]

Why do people here keep on forgetting that more buses = more drivers = higher operating costs? Is this a short-term memory thread?

[waterloowarrior]

West Side Action has a bunch of pictures and discussion on how this will affect west side residents
http://www.westsideaction.blogspot.com/