Full slide deck:
Ignorant question, given Bombardier's suggestion on slide 19: does it make any sense to electrify the inside 128 portion of all lines (or all Southside/Northside lines) at once and then extend out?
Substation placement charts where freshly electrified territory racks up. In the case of the Fairmount Line it's chaining off the expansion of existing NEC Sharon substation, which covers the South Station terminal district.
Sharon sub, located at about the two-thirds point between Canton Junction and Sharon stations and 1000 ft. south of some major feeder lines, has a mostly blank site as shown on Google. That has site capacity to get infilled with new sub for an expanded terminal district, 4 wired NEC tracks throughout MA carrying 2040-level Amtrak traffic and RUR-level Providence traffic, 2 wired tracks of full Fairmount Urban Rail traffic and interlined Franklin/Foxboro RUR traffic, and *maybe* the Riverside Urban Rail line (or at least starters before terminal district backfill forces the innermost B&A to get switched to the nearest MetroWest sub's feed).
25 kV AC is an international standard, and Amtrak's New Haven-Boston electrification produced a long specs guide that Denver RTD, Caltrain, CAHSR, and GO Transit are all following. The substations are the source of all power, located near high-tension power lines (all pre-existing for AMTK, with any power boosts just augmenting the lines already on the power company ROW). Subs are located in the
middle of power sections, with the endpoints of each section marked by switching stations. The absolute endpoints of the electrification--i.e. the phase break to Metro North's 12.5 kV system and the bumper posts at South Station--are situated more or less equivalent to where another set of switching stations would be for continuing the 25 kV service. For instance, when NSRL is built, it'll have an underground switching station breaking up the southside/Sharon power section from the first northside section.
- South Station endpoint: Milepost 228
- Sharon, MA substation: MP 212; 17 miles from South Station (and/or future NSRL switching station)
- Norton, MA switching station: MP 199; 29 mi. from SS; ↓13 mi. from Sharon sub, ↑22 mi. from Warwick sub
- Warwick, RI substation: MP 177 (1000 ft. north of T.F. Green platform); 51 mi. from SS; ↓22 mi. from Norton switch, ↑27 mi. from Richmond switch
- Richmond, RI switching station: MP 150; 78 mi. from SS; ↓27 mi. from Warwick sub, ↑27 mi. from New London sub
- New London substation: MP 124 (State Pier next to Thames River Bridge); 104 mi. from SS; ↓26 mi. from Richmond switch, ↑21 mi. from Westbrook switch
- Westbrook, CT switching station: MP 103; 125 mi. from SS; ↓21 mi. from New London sub; ↑24 mi. from Branford sub
- Branford, CT substation: MP 79 (2 mi. west of CTrail Branford station, off-ROW w/ feeders trenched under I-95); 149 mi. from SS; ↓24 mi. from Westbrook switch, ↑5 mi. from New Haven phase break
- Mill River phase break (changeover to Metro North 12.5 kV): MP 74 (3/4 mi. north of State Street Station, immediately before Springfield Line split)
Lengths of power sections:
- Sharon sub (South Station to Norton): 29 miles
- Warwick sub (Norton to Richmond): 49 miles
- New London sub (Richmond to Westbrook): 45 miles
- Branford sub (Westbrook to Mill River): 29 miles
Sharon is a shortie because it powers the Boston terminal district. Branford is a shortie as provision for absorbing the first power section of the Springfield Line when fully built out, so in the future it may be sharing the load up to about Wallingford (NHV terminal district is all on the MNRR 12.5 kV network). The others are representative, including the fudge factor for placements near power lines. Note that these spacings stay constant despite traffic levels and # of wired tracks, as they're based on voltage losses and not load factors. For heavier-load sections (like Sharon) you simply build a bigger sub, stuff it with more equipment, and feed it with brawnier transmission lines.
The only other structures are on-ROW paralleling stations, which are basically localized circuit breakers. There's 18 of them scattered along the NHV-BOS electrification at approx. 7-mile intervals between the larger subs & switching stations. The SW Corridor, for instance, has 2 of them:
Roxbury halfway between Ruggles and Jackson Square OL stations, and one at
Readville sandwiched between the NEC and NEC-Fairmount connector. Since the Fairmount Line will be parasitic to Sharon sub, it would need about 2 of these...one inside of Southampton Yard to break it from the yard feed, and one somewhere in the Talbot-Morton stretch.
I honestly don't know where this would chunk out in terms of "Can you build 128-turning lines first?", because the layout goes by its own voltage distances and not necessarily service distances. On the southside it's reasonable to figure that Franklin/Foxboro are going to be powered by a sub in Walpole near the prison right on the start of the Framingham Secondary because there's some monster-ass high-tension lines converging there...and the distances agree for a sub based there and a switching station at Readville. Worcester Line I'm thinking that MetroWest hosts the sub because there's some big lines a stone's throw west of Framingham...but there's probably a switching station somewhere in Newton cleaving off from the terminal district feed. Stoughton is no-go for any electrification until you make decisions on whether South Coast Rail Phase II is happening, because it's too much for Sharon sub and the ideal power lines are in that blasted swamp in Easton. Old Colony's going to be pricey as you'll need one sub close to Braintree feeding the main + starts of all 3 lines then one each per branch further out. But you aren't wiring those any which way until the Dorchester pinch is fixed.
Northside...who knows. You have no shortage of lines running right along the Eastern Route, so you're set for Rockpeaburybodyport wiring and 2 subs powering all. The question is "who's Sharon-North?" that powers the terminal district so you know where things are phase-breaking from each other at a switching station. Waltham has a shitload of converging lines and the Fitchburg Line is branchless, so it may make sense to plunk the Terminal District feeder out there. Inner Lowell + Reading Line have somewhat dearth of lines inside of Woburn & Reading so there'll have to be some artful phase-breaking there with some lines having nearer subs so others can have further-out. None of it that big a deal...it's just not something you can easily conceptualize in your head vs. a service zone map that breaks Urban Rail vs. RUR almost always @ 128. You shoot for how many new service rungs each pricey sub nets you, but can't necessarily count on it being "all the Urban Rails first" because the service buildout yardsticks vs. electrification buildout yardsticks don't have the same common denominators.
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