Tunnels!

[talindsay]

Back in 2003 I asked a Met Council person why they hadn't considered elevating the (Hiawatha) line through downtown to remove grade conflict and the dude laughed dismissively, saying it would interfere with the skyways. That seemed like an unsatisfactory response to me, but Metro Council has clearly never taken elevated lines in the downtown seriously. And to be fair, they *are* ugly and disruptive, and the skyway problem is real.

I've also heard that our tunneling costs are relatively low compared to most places, and so the cost difference between elevating and tunneling is smaller than in most places. Basically if it's not worth tunneling here, it's not worth elevating either given the small difference in cost and the substantially higher disruption and environmental impact of elevated rail.

[DanPatchToget]

While Miami doesn't have skyways (that I know of) their Metro Rail is elevated above their People Mover system in downtown, so that's probably the closest example of what elevated rail in Downtown Minneapolis would look like. I don't think anyone is proposing building the tracks through the skyways and then we have to deal with many grade crossings in skyways, but rather have the tracks go above the skyways.

[Tcmetro]

I think the downtown at-grade alignment is fine. Considering there's no long-term plan to add a third line to the 5th St corridor there isn't much need. I'd even be surprised if 7.5 min peak frequencies come back before the next decade.

As for the cheap tunneling, I believe it was first considered in the late 60s. The idea is that limestone is relatively easy to dig through. The problem is that the limestone layer is like 80 feet below ground, so stations would be quite expensive to build. The initial subway plan had stop spacing of 1-3 miles.

[DanPatchToget]

I think the downtown at-grade alignment is fine. Considering there's no long-term plan to add a third line to the 5th St corridor there isn't much need. I'd even be surprised if 7.5 min peak frequencies come back before the next decade.

As for the cheap tunneling, I believe it was first considered in the late 60s. The idea is that limestone is relatively easy to dig through. The problem is that the limestone layer is like 80 feet below ground, so stations would be quite expensive to build. The initial subway plan had stop spacing of 1-3 miles.

From a near term perspective yes the 5th Street Corridor does the job. Long term however, I don't think it's in our best interest to rely on a corridor that's already at capacity.

[Nick]

Man, does anybody remember the argument on here like six or seven years ago about whether or not train frequencies would increase on 5th Street with the Blue and Green Line extensions?

[Anondson]

All the time.

[Tom H.]

Vividly.