In June, the preliminary options under consideration for the B&P tunnel replacement were presented to the public. You can find the display boards
here.
The options still under consideration are:
1) No-build.
2) Reconstruct B&P tunnel.
3) New curved tunnels with four tracks (most likely in 4 separate tunnels).
11) New straight tunnels with four tracks (most likely in 4 separate tunnels).
Both 1) and 2) would only have 2 tracks, which is not enough to accommodate the number of trains expected by 2040. Option 1) would not be able to accommodate double-stacked freight, and option 2) would require shutting down the NEC south of Baltimore (not going to happen).
Options 3) and 11) have multiple sub-options. These mostly differ in the southern portals, near the West Baltimore MARC.
For each of the options, they provide the estimated value of annual time savings in
2015 dollars. They also provide capital cost estimates in
2023 dollars. For clarity I've converted those to 2015 dollars assuming a 3% construction inflation rate, which seems to be typical for these studies. Add about 25% to these numbers to get costs in 2023 dollars. (Unfortunately, as we saw in the Red Line debate, this will inevitably lead to people eight years from now complaining about how costs have gone up dramatically from initial estimates.)
So here are the options:
2
Value of time savings: $0 million
Capital cost: $0.55 billion
Southern portal: Same as now.
3A
Value of time savings: $32.5 million
Capital cost: $2.92 billion
Southern portal:
3B
Value of time savings: $43.4 million
Capital cost: $3.16 billion
Southern portal:
3C
Value of time savings: $42.3 million
Capital cost: $3.32 billion
Southern portal:
11A
Value of time savings: $46.8 million
Capital cost: $2.92 billion
Southern portal:
11B
Value of time savings: $45.5 million
Capital cost: $3.16 billion
Southern portal:
3A is the least disruptive, maintaining the current alignment through the West Baltimore MARC. But it's also the slowest, as through-trains will need to slow down to get around that curve. The others all straighten out the curve some way.
11A looks good on paper, but it would be hugely disruptive to the neighborhood and would require re-locating the West Baltimore MARC station to the south. 11B is similarly disruptive. I'd guess that at this point, 3A or 3B are the most likely.
There's another option that I didn't see discussed: build only 2 new tunnels, and while those are in service reconstruct the existing B&P tunnel. The reconstructed B&P tunnel could be used for local service (and potentially connect to the Metro at Upton), and the new tunnels could be used for high-speed through service. Assuming that 2 tunnels would cost about half as much as 4, a rough cost estimate for this hybrid option would be roughly:
$1.55 billion for the 2 new tunnels + $0.55 billion to reconstruct the existing B&P tunnel = $2.1 billion.
It would probably be a little more than that in reality.