O-Train Line 2/4 [Stage 2 | Greenboro to Limebank/Airport] | In Service - Page 44

OCCheetos · #**861** Posted **Nov 29, 2018, 6:16 PM**

GeoOttawa still hasn't been updated with the alignment to Limebank or the inclusion of the grade separation at the Ellwood diamond. Is it possible they forgot to update it? Guess it can't hurt to ask.

OCCheetos · #**862** Posted **Jan 17, 2019, 3:00 AM**

Some new details were posted on the O-Train Fans Forum.

Apparently the design of South Keys has been changed and will instead be a three-platform station. The specifics are being left up to the bidders (I guess this might explain some of the delays) and so there isn't any publicized documentation yet and why geoOttawa hasn't been updated recently (according to the poster).

Generally, "flexibility" seems to be the keyword so plans might still change.

lrt's friend · #**863** Posted **Jan 17, 2019, 4:01 PM**

There are pros and cons of this latest proposal.

The last I heard with regards to the shared Trillium Line station at South Keys is that airport spur trains had to arrive midway between mainline trains and somehow, the spur trains had to clear the station and go into a pocket track and likewise in reverse. This may have been seen as difficult to manage. Also, delays on either the mainline or the airport spur could impact the whole Trillium Line. This is already an enormous risk with its single track restrictions.

The new concept isolates mainline and airport spur trains so they are not sharing track at South Keys. This will be operationally more simple. Problems on the spur and mainline do not impact the other. Furthermore, train arrivals and departures can be better timed.

The down side of this is that it won't be possible to transfer from the main line to the spur or reverse using a shared platform, at least not in all cases. For example, the airport spur train arriving at South Keys, will require the passenger to cross over the south bound mainline tracks. This will be done by either an elevated walkway or a tunnel. This will take a few minutes to do this, whereas a shared platform is a matter of getting off the airport spur train and waiting for the mainline train on the same platform.

I expect that train timing will mean that there will not be much difference other than the extra walking and stair climbing.

This could also mean that the Hunt Club crossing may have to be triple tracked to keep airport spur trains totally isolated.

HighwayStar · #**864** Posted **Jan 17, 2019, 4:12 PM**

Quote:

Originally Posted by lrt's friend

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The new concept isolates mainline and airport spur trains so they are not sharing track at South Keys. This will be operationally more simple. Problems on the spur and mainline do not impact the other. Furthermore, train arrivals and departures can be better timed.

The down side of this is that it won't be possible to transfer from the main line to the spur or reverse using a shared platform, at least not in all cases. For example, the airport spur train arriving at South Keys, will require the passenger to cross over the south bound mainline tracks. This will be done by either an elevated walkway or a tunnel. This will take a few minutes to do this, whereas a shared platform is a matter of getting off the airport spur train and waiting for the mainline train on the same platform.
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Other than the engineering logistics, why can't the airport spur be designed to be the middle track?

zzptichka · #**865** Posted **Jan 17, 2019, 6:34 PM**

Well if you have to go up and down the platform to transfer to the airport train then it's a joke.

Middle track for the Airport spur where doors open on both sides seems like an obvious and elegant solution in this case.

J.OT13 · #**866** Posted **Jan 17, 2019, 6:43 PM**

The issue with having the airport line using the middle track is that it would need a level crossing, which could screw with the schedules, or have pass under or over, the main line, which would be expensive. That would be the best case scenario however, operations and convenience wise.

lrt's friend · #**867** Posted **Jan 17, 2019, 6:47 PM**

Quote:

Originally Posted by J.OT13

The issue with having the airport line using the middle track is that it would need a level crossing, which could screw with the schedules, or have pass under or over, the main line, which would be expensive. That would be the best case scenario however, operations and convenience wise.

Exactly what I was thinking. To avoid another grade separation to allow the spur to enter as the centre track, the airport spur has to run on the west side of the main line creating the scenario that I described.

HighwayStar · #**868** Posted **Jan 17, 2019, 6:54 PM**

Quote:

Originally Posted by J.OT13

The issue with having the airport line using the middle track is that it would need a level crossing, which could screw with the schedules, or have pass under or over, the main line, which would be expensive. That would be the best case scenario however, operations and convenience wise.

Wouldn't they have to go over/under the Airport parkway anyway? If they went under, there should be a reasonably cost effective path under the main line... especially since this is all new construction.

zzptichka · #**869** Posted **Jan 17, 2019, 7:18 PM**

Quote:

Originally Posted by J.OT13

The issue with having the airport line using the middle track is that it would need a level crossing, which could screw with the schedules, or have pass under or over, the main line, which would be expensive. That would be the best case scenario however, operations and convenience wise.

Since the spur is very short, there could be a conflict only if main line schedule was already screwed up.

Catenary · #**870** Posted **Jan 17, 2019, 10:57 PM**

If the track south of SK is single tracked, then it doesn't really matter which platform is where. If the track is double tracked, and they maintain each track operating in a single direction, then the airport trains will be northbound on one track and southbound on the other just like any other train, so the middle platform would work well and the only conflict would be at the turnout to the airport.

If they double track from SK to the airport spur and treat each track like it is a single track, then you have to keep the airport service separate. The conflict in option 2 can be removed with an eventual flyover when frequencies require it.

roger1818 · #**871** Posted **Jan 18, 2019, 2:21 PM**

Quote:

Originally Posted by Catenary

If the track south of SK is single tracked, then it doesn't really matter which platform is where. If the track is double tracked, and they maintain each track operating in a single direction, then the airport trains will be northbound on one track and southbound on the other just like any other train, so the middle platform would work well and the only conflict would be at the turnout to the airport.

If they double track from SK to the airport spur and treat each track like it is a single track, then you have to keep the airport service separate. The conflict in option 2 can be removed with an eventual flyover when frequencies require it.

I know GeoOttawa hasn't been updated, but it currently shows something that is closest to that third option (with a crossover just south of Hunt Club). It wouldn't be much more expensive to switch to your option 2 having crossovers near the centre split at South Keys and the diverge further south to maximize flexibility.

Gat-Train · #**872** Posted **Jan 18, 2019, 4:42 PM**

Is the line south of Greenboro going to be double tracked? Seems to me that would make the most sense. Why not build it double tracked now, especially seeing as how at some point in the future the whole line will be double track, and thus we could save ourselves a lot of headache in the future

OCCheetos · #**873** Posted **Jan 18, 2019, 5:00 PM**

Quote:

Originally Posted by Gat-Train

Is the line south of Greenboro going to be double tracked? Seems to me that would make the most sense. Why not build it double tracked now, especially seeing as how at some point in the future the whole line will be double track, and thus we could save ourselves a lot of headache in the future

The plan on geoOttawa is for there to be a single mainline track (with a second track leading to the airport running alongside it) between South Keys and Leitrim. From Leitrim onwards is full double track. The section between SK and Leitrim is straightforward to double track in the future though.

lrt's friend · #**874** Posted **Jan 18, 2019, 9:40 PM**

It seems to me that there will be some rather complicated train maneuvers and signalling if the airport spur is the centre track at South Keys. Unless there is a flyover, which will require the southbound track to be bayed out to the west to accommodate the flyover, we are talking about two southbound trains crossing each other's path. The simplest approach is to have the airport spur be the most westerly track at South Keys so there is no cross-over required. Any train crossing operation will require a degree of train separation just as we already see at the passing tracks and to allow VIA trains to safely cross at Ellwood Junction. We are not going to see two southbound trains leaving South Keys 30 secounds apart.

roger1818 · #**875** Posted **Jan 19, 2019, 1:02 AM**

Quote:

Originally Posted by lrt's friend

It seems to me that there will be some rather complicated train maneuvers and signalling if the airport spur is the centre track at South Keys. Unless there is a flyover, which will require the southbound track to be bayed out to the west to accommodate the flyover, we are talking about two southbound trains crossing each other's path. The simplest approach is to have the airport spur be the most westerly track at South Keys so there is no cross-over required. Any train crossing operation will require a degree of train separation just as we already see at the passing tracks and to allow VIA trains to safely cross at Ellwood Junction. We are not going to see two southbound trains leaving South Keys 30 secounds apart.

It isn’t as complicated as one would think. South Keys is a passing track for the north and south trains, so both will be there at the same time. Also, for optimal transfers, the airport train will need to arrive just before the northbound train arrives and depart just after the southbound train departs.

To achieve that, the airport train can always use the western most track and the trains to/from the south always use the eastern track. Obviously northbound both trains can head into the eastern and central platform tracks easily. Southbound, the airport train waits for the southbound train to leave, cross over from the western platform track to the eastern track, clear the switch, for the switch to throw, and for it to get the all clear. It’s can then proceed to the airport on the western track. Since the route to the airport is shorter, the extra delay should be inconsequential (certainly less than was panned with only 2 platform tracks).

J.OT13 · #**876** Posted **Jan 19, 2019, 2:12 PM**

Quote:

Originally Posted by HighwayStar

Wouldn't they have to go over/under the Airport parkway anyway? If they went under, there should be a reasonably cost effective path under the main line... especially since this is all new construction.

It will go under or over the Parkway 750 meters before it reaches the main line.

Gat-Train · #**877** Posted **Jan 19, 2019, 4:00 PM**

I know the point is moot, but the airport spur seems like such a large amount of money for such a short line. As I've said before, it would definitely be possible to continue that line on existing track, possibly even to Hurdman, so that it would give a few more options for travellers and eliminate a transfer

J.OT13 · #**878** Posted **Jan 20, 2019, 4:00 AM**

It is a short line, but eventually it will go all the way to Bayview. Hopefully, we won't need to wait too long. And the City isn't investing any money in this; the Feds and Province splitting most of the cost with the airport picking up the tab for its own station. Not perfect, but a good start.

roger1818 · #**879** Posted **Jan 20, 2019, 4:17 AM**

Quote:

Originally Posted by J.OT13

It is a short line, but eventually it will go all the way to Bayview. Hopefully, we won't need to wait too long. And the City isn't investing any money in this; the Feds and Province splitting most of the cost with the airport picking up the tab for its own station. Not perfect, but a good start.

I don’t know about unless something dramatically changes. The new, higher capacity trains are expected to meet the line’s needs for some time to come. A lot depends how frequent they can actually make the service after Stage 2. If I were a betting man, I would say 30 years

Catenary · #**880** Posted **Jan 28, 2019, 4:25 AM**

I noticed today that SNC-Lavalin has posted a position for a Maintenance Director for a DMU operation in Ottawa. Bombardier has the current contract, so this seems unlikely to be related. It was posted a while ago.

https://slihrms.wd3.myworkdayjobs.com/en...ite-1100/Maintenance-Director_R-021107-2

Is SNC going to be on the winning consortium, or is this posting just speculative?