I read F-Line's post in the other thread regarding using the space under the Big Dig freeway. The new RR tunnel would be in fill, under the highway and between the slurry walls. Since the slurry walls leak, the fill soil would be saturated. Is there a boring method that is so sensitive in saturated soils that it could bore without undermining the highway above?
cudjoebobI think the Big Dig trench blocks any possibility of connecting North Station to South Sta.
I think the Big Dig trench blocks any possibility of connecting North Station to South Sta. North Station is on the west side of the 'Dig' and South Station is on the east side of the trench. too bad it wasn't done decades ago. it's too deep to try to 'cross' the trench by digging a rail tunnel crossing underneath the trench. what are the chances of a light rail system running up the Rose Kennedy Park?
I imagine a cost-benefit study would be run, with the choices of:
1. Continiue diesel operation of all suburband service, with a high-capacity ventilation system (very expensive) with all possible treatment and mitigation. Amtrak through trains would change power at South Station, similar to what is done at Washington, DC.
2. Third-rail elelctrification of the tunnel and adjoining platforms and approaches. The major and through-routed suburban lines, and Amtrak's Downeast locomtives would be dual mode. Again, Amtrak would change engines at South Station.
3. AC catenary electriciation of major suburban lines and the tunnel and its approaches. The NEC south to Providence would need increased substation capacity, but no changes to the overhead. Amtrak could change engines at either Haverill or North Station, sort of corresponding to their choice of either Harrisburg or 30th St. Philly for the Pennsylvanian and any restored 'Broadway (I am holding my breath, sure?)
Since we are talking about a pair of "thru terminals", I would expect a equal number of trains coming inbound from their respective north and south suburbs, stopping at both stations, where there may be a subequal number of passengers de-training at both stations, and maybe some reverse commuters getting on, and then those trains continuing on to the opposite ends of the line from which they started from. This seems like how Reading/Phily Suburban operate.
Major thru stations like NYP and Reading/Phily Suburban are electrified. Will Boston's tunnel be electrified with complementary electrification of some major North commuter line? If not, then they will have to deal with objectionable fumes coming up from the tunnels in the middle of downtown.
The length of the station and approach tracks can provide a slope to a fairly deep tunnel while retaining the present six-track (fomerly eight) bridge crossing of the Charles River, and no tunnel under the Charles is necessary. The replacement North Stationi platforms would be straight, but on a grade, and that should be no problem. I would imagine four of the present stub tracks at North Station being reploaced by inclined tracks with two platforms, and the four tracks merging to two in an underground throat under the present building and Causeway Street, with the two-track tunnel having the reverse arrangement at South Station. Of course at each end, all four through stationh tracsk would have access to both tunnel tracks. In the morning at both stations, normallly three tracks would be used for inbound trains and one for outbound, the reverse in the evenking. The reason? Iin bound trains speend more time at the station platforms and outbound trians more time in the evening. Othrwise, the number of trains in both directions would be balanced, both morning and evening. Normally, the outer of the four tracks would be single-directional, with the two middle tracks reversed morning and evening rush hours. The two track tunnel should be able to handle trains on a two-minute headway each way. The scheme would be planned so a second tunnel could be added without closing down the first.
I have trouble envisioning this project. Presumably it would have to be tunneled very deep with long approaches.
A tunnel under the Charles River? Any speculation on the route or station modifications? This might make the Big Dig budget look like pocket change .....
Links to my Google Maps ---> Sunset Route overview, SoCal metro, Yuma sub, Gila sub, SR east of Tucson, BNSF Northern Transcon and Southern Transcon *** Why you should support Ukraine! ***
I remember that this connection was part of the discussion about the Big Dig design. After several lawsuits, I seem to remember that the tunnel design was supposed to be modified to include extending the sidewalls deeper under the roadway level. Think of a box with the top and sides, but no bottom. This would make excavation for the rail tunnel easier. I don't know if the road tunnel was actually constructed like this, or if it was just a proposal that got lost in the Big Dig. Anyone know?
It should happen, but it might take a generational change until they forget about the Big Dig.
Correct and important
Boston Globe Op-ed by Dukakas promoting the connection. Only about reasons not how engineering.
http://www.bostonglobe.com/opinion/2015/08/18/michael-dukakis-and-william-weld-build-north-south-rail-link/Q8F7VVAOFPl55HOf48JrEP/story.html
Our community is FREE to join. To participate you must either login or register for an account.