This thread seems to be getting sidetracked by someone's fantasies.......... This thread is not about the Ontario Line or any other tech in the Lakeshore Corridor, it is solely, and entirely about the northern extension of the Ontario Line, from its eastern terminus.
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That said,
@junctionist had me curious about transit times, obvviously I don't know his inlaws address, so I just plugged in GO Burlington Station as the start point just to see, what the route times were and if there was any room to lower those materially, after which such discussion could be moved somewhere more material.
For the Airport, I got 1 hr 28 from Burlington GO Stn, using the 407 bus connection.
The trip via Union, (train) then UPX gets you 1 hr 49
I'm not sure how one could the bus'es travel time.
The rail connection shows 1hr 4M from Burlington to Union, which likely makes the case for an express option not available today.
Resetting the date/time to use a GO Express train, cuts the train trip from 1hr 4 to 51M and produces an overall travel time of 1hr 32M.
Other than a modest further reduction from electrification, I'm not sure you get that number much lower, unless GO Rail Corridor operates roughly from the airport to Burlington via the 407 corridor for the most part.
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Travel to Square One:
Best travel time via bus: 1hr 5 with the 407 corridor (2) then the 40
Best travel time via Train (LSW): 1hr 26 (takes you to Oakville where you catch the 56)