Attempting to move some more fantasy-like discussion from the BIRT thread to this thread.
One thought I had is that it's not unreasonable to request that BC Hydro undergrounds the 230kV overhead lines from the top of Boundary to the Horne Payne substation. If that were done, Boundary Road would be the perfect RoW to deliver a Skytrain line.
Undergrounding the 230kV overhead lines isn't just unreasonable, it's rooted in reality.
In 1995 the cities of Vancouver and Burnaby specifically appealed to the BC Utilities Commision to request that BC Hydro underground the overhead lines. This request was rejected on the basis of 3 reasons, #1 BC Hydro was authorized to use the right of way (this was in question apparently) so no one was making them move, #2 the overhead lines still had 20 years of useable life left, and #3 the reason for the request was determined to be primarily for beautification purposes. However, the commission noted that if Burnaby and Vancouver were willing to foot the bill themselves it was a done deal.
30 years later, the case may be far stronger. If the overhead lines had 20 years of useable life left, that's all but evaporated now, and there might be a very practical reason to underground now. With the overhead lines out of the way, there is a clear and obvious right of way from the Second Narrows all the way to Gilmore Station.
The route would cross the Second Narrows and enter a cut-and-cover tunnel at the north end of Boundary. The section through Burnaby Heights would have to be below grade by necessity as the grade is far too extreme for the Skytrain, but if the overhead lines are undergrounded beneath either the north or south lanes of Boundary it should be fairly trivial and cheap to build this section via cut-and-cover. If we assume a 4% maximum grade from the end of Boundary, the maximum required depth would be around 20m at McGill and Boundary which isn't completely outside the realm of possibility. This "deep trench cut-and-cover" would only have to run from the end of Boundary to around Cambridge. If desired, a future infill station could be roughed in here. From there a "shallow trench cut-and-cover" where the line will only have to duck under the existing roads can run until Triumph. This section would still have to be below grade in order to have a reasonable height for a station at Boundary and Hastings. Because of the topography it should be simple for the line to transition from below grade to above grade just before Hastings. Building the Hastings station above ground will be cheaper, and will also make building any future Hastings Line connection station easier. Conveniently, this station will be relatively close to Kootenay Loop which means existing bus infrastructure for transfers can be reused. Heading south will be slightly awkward because of the topography as the guideway at around Francis will be about 30m high, but other than that the guideway can continue down Boundary extremely uninhibited. This route also runs directly past the CMBC Burnaby Transit Centre which may be perfect to commandeer for the line's OMC. Following the completion of the Hamilton Transit Centre and the future Marpole Transit Centre, this land might not be required for CMBC anymore. The entire depot doesn't need to be taken, but the north lot is probably not large enough so I think at least the south lot is necessary. Potentially another infill station could be designed for here in the future. At 2nd, the guideway can then cross the FortisBC and OpenRoad lots to follow Chubb Creek over to Gilmore Station for a connection before crossing the railway tracks for a straight shot back towards Willingdon and eventually BCIT.
Here's a map of what I mean.
Lighter purple is cut-and-cover, darker purple is elevated.
Although it's not perfect, this alignment provides a slightly better connection to Burnaby Heights than a route along HWY1, and minimizes any excavation needed unlike any other route through The Heights.
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Originally Posted by waves
There are a number of possibilities for Willingdon alignments that do not require a bored túnnel. I take issue with the presumption that a Willingdon alignment is "billions" more than an above ground highway to Gilmore alignment.
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Never said billions, just one single billion.
Let's be honest, a Brentwood interchange is inherently the more expensive option when compared to a Gilmore interchange. The question is just whether the savings justify the somewhat lesser station.
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The second issue I have is the assertion that a station on stilts 30m in the sky is somehow equivilant to a station 30m underground. These are two completely different engineering problems and not a reasonable comparison. There are certainly examples of the guideway being high as has mentioned but not a full fledged 100m long station building. There is simply no equivilant station structure in the entire Skytrain network located so high off the ground. For the option of a station directly west of Gilmore it would still need to be exceptionally high as the track still needs to go over the guideway. North South along Gilmore is also a more expensive alignment than Willingdon with steeper grades and complex expensive utilities under the street.
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You're right, it should be a significantly easier proposition. a 100m long station building being built on "stilts" is a bit of an exaggeration. Guideway pillars are bit more than glorified stilts. Not sure where you got 30m from, but I can assure you that designing a station on concrete pillars 20m (and 20m was the conservative overestimate) high rather than a station on concrete pillars 13m high is not an extremely insurmountable challenge.
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With the available SE corner of Willingdon and Lougheed, the ample space along Willingdon for cut and cover, and the option to be above grade along the south shore as shown in my original post (meaning no expensive bored tunnels), I am unconvinced that Gilmore is a more reasonable or even cheaper option for the interchange.
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You are still presupposing that Alpha is an available RoW. It's convincing, but considering you need to acquire that entire property and cut-and-cover the length of Willingdon, I find it extremely unconvincing that an elevated-only line would somehow be cheaper than a Willingdon cut-and-cover line.
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