These people would need to transfer anyway.
Okay. Get ready for some math. We all love math right? HAHA
This might be hard to follow on your phone due to tables.
So this is old (2005 ish), for the 1.5 million population horizon. Lets accept it as true.
It is: "Projected AM Peak Hour / Peak Direction LRT Ridership and Train Requirements Entering Downtown"
Now, that adds up to 27,200 entering from the east side, and 9,200 entering from the west side.
When this report was written (2004-2005, likely from 2003 data), demand was 6,600 from the south, and 4,700 from the north east, and that was maxing out comfortable capacity already.
11,300 divided by 180 average per hour capacity per car = 62.8 cars divided by 3 car trains, 21 3 car trains, or service just above one train every 3 minutes.
This capacity was considered maxed out to the point where the work to switch to 4 car trains was already beginning.
So now, more math.
4 car trains * 180 people * 28 trains per hour (this would be pushing it, but lets be ambitious) = 20,160 people of capacity. A shortfall of 7,000 people of capacity at the 1.5 million population horizon.
Now, if you think of downtown as a single destination, a single node, a single station, the Gray group proposal seems smart. It adds capacity at a super low cost. Easy Peasey.
But it breaks down when you start thinking about flows within downtown.
Here is the 3rd St SE station 600m catchment vs a 2nd street SW catchment:
So you'll have attempts at transfers, at City Hall. We can look at presumed day 1 conditions, since the city is at the population threshold already.
Now I am going to build a very simple model. I assumed 25% of all demand coming in from the east will go east or get off at city hall. East in this case means anywhere east of the city hall station, so it includes red line south.
So just with the SE you have:
At 25 years of 1% demand growth, you breach the capacity limits:
Now we can also add in North Central via the blue line.
Which breaks capacity on day 1:
And in 25 years requires an extra 8 trains an hour above theoretical capacity:
So doing the Jim Gray 'solution' locks Calgary to starting the Red Line tunnel at the very least by 2040 if one is building the Greenline SE, or simultaneously if one builds the North Central Greenline too.
If one builds a different solution for the Green Line(s), which doesn't overburden the cuplet from the east, a Red Line tunnel could start construction as late as 2070.
How much more would an elevated solution at 2nd Street SW cost over an elevated solution at 3rd Street SE? It would be less than 1000 meters of elevated guideway and maybe a station. You're talking what, $500 million extra (which is likely a vast over estimate) for a vastly superior transit implementation