BostonUrbEx wrote:By the way, on those Eastern Ave Grade Separation plans, IIRC, the plan was for the road to go over the tracks, correct? Is going under not feasible due to the proximity of the Chelsea Creek?
Not sure, since the '04 Study only published that one preferred rec for a road bridge and didn't do any document dump of all the rejected alternatives. Because the study was so broad in scope they didn't have bandwidth for pubbing an extra thousand pages from the cutting room floor informing how they culled the universe of possibilities into a final series of pan- North Shore transit recs.
Wouldn't be difficult at all to do as rail-over-road. There's a 2000 ft. straightaway north between Eastern Ave. and the Forbes St. overpass...more than enough to build the embankment up on gentle 1% or less grade and bridge over Eastern at 16 ft. default overhead clearance for a truck-carrying arterial. It's 950 ft. tangent to the south of Eastern before start of the curve, but (1) it's a slight curve and (2) moving the last couple power line towers before they turn out into the Box District substation can widen out that straightaway to up to 1200 ft. before the slightest of curve begins near bottom of the incline. Meaning you should easily be able to keep an equally gentle 1% or less grade on that side too. There's derelict sidings on both sides of the crossing and no need to provision for any future side-by-side Silver Line spur on this side of the ancient Grand Junction/Eastern RR wye, so building up the sides of the embankment within existing property lines shouldn't be an issue either.
If I had to guess, cost of the road bridge probably ended up cheaper than building up a rail embankment because of the much more compact project area. It isn't that the EIS'ing would've been in any way hard for a rail embankment + overpass since the surrounding land is all brownfields and/or very polluted riverbank. But it's more linear feet & acres worth of land permits, more quantity & types of permits encompassing more heterogeneous land use (small stretch of river shore, brownfield private property backlots, the electric utility, and more-varied private abutters). So tally up all the extra paper-pushing for the larger project area and I would not be the least bit surprised if the price tag ended up a few $M inferior to a road overpass any way you design it. All despite the somewhat better conceptual 'cleanliness' of a rail bridge that doesn't need to alter any abutting driveway access like the road overpass would.
All relative, as that whole stretch of Eastern south of Webster Ave is a permanently industrial eyesore that needs no special accommodation. Either method probably priced out pretty cheap in absolute costs. $19M in '04 $$$ was a downright bargain for a perma-fix for that onerous speed restriction and scary safety risk with the bad-angle crossing of a speed-trap arterial full of 24/7 leadfooted gas tanker drivers. With MassDOT more experienced today at prefabbing bridges quickly...and river barges 1200 ft. down the street @ Global Petroleum being able to float giant pieces to the site...they could probably hold the line close to that cost 15 years later simply through all the gained construction efficiencies canceling out most of the accrued inflation.
The only reason this proposal--like nearly all eminently sensible and high-ROI recs from that study--were never implemented was because of total Beacon Hill indifference. They built the white elephant garages years late and hugely over-budget, and tried to pass that off as GLX delay mitigation (!!!)
of all things. Were it not for that passing the laugh test by the slimmest margins, it wasn't even guaranteed that parking-mad Massachusetts would've been self-motivated enough to even finish the job on the two garages given how long those also dragged out. The whole North Shore is a longstanding transit anti-priority in the Legislature. Something as function-over-form as a crossing elimination never would've stood a chance given how little follow-up was given to all the much higher-profile service increase and steel/concrete station edifice stuff in those long-suppressed study recs.