The two track replacement of the Portal bridge is $1.5B now. That $800M estimate of yours is likely too low. The real cost will come of they insist on keeping the service operational at the existing level while the bridge is being replaced. The only possible location for a second bridge while the existing one is still in service is to the south. The problem with that is that then they will need a NEW three track viaduct from about Broad Interlocking to the river plus a NEW three track viaduct from the river to at least Hamilton St in Harrison. These will require acquisition of the two lots with the junky containers on both sides of McCarter Highway plus the triangular parcel on the corner of Passaic and Hamilton on Harrison. In my opinion all that is going to be very expensive and unnecessary. The thing to do is to put the third track on the north side of the existing tracks. That is easy -- no property acquisitions, no NIMBY because the track will go on the side of the highway. The clover will need a little modification, the tower even if it is historical needs to go. Then put a single track lift bridge on the north side. Either close the river or operationally, the lift bridge will need to go up first, then lift the existing swing span, but my preference is for 2-3 year river traffic closure. Then cut reverse peak service and run the peak service on the single new span while replacing the swing bridge and its approach structures. Commute will suck for about 2 years due to the single tracking, but this avoids property acquisitions and allows for reuse of any of the existing approach structures and fills that are in good condition. Of course value engineering is all forgotten once politicians start pandering to the electorate. I am ready to bet that the southern location will get chosen in the final design.
I don't think property acquisition to the South will be required. Once the Rt 280 / Rt 21 intersection improvements are complete, the clover ramp from 21 to 280 east will be demolished, making room for a realignment to the North on state owned land.
http://www.state.nj.us/transportation/c ... ements.pdf" onclick="window.open(this.href);return false;
As you stated, they could close the river to traffic for the duration of the project. That would allow a temporary bridge to be built, possibly relatively cheaply as they could just pile drive right into the river bed for support - no span - just a ton of steel beams and temporary support structures. That temporary bridge and viaduct could maintain two tracks, as they rebuild the current bridge into a new three track configuration, possibly as a draw bridge. Then demolish the temporary bridge and reopen the mainline on the current alignment.