Fully double track old colony lines

(could apply to any commuter rail or transit line) Is it really a significant operational problem to have isolated single track sections, not more than a half mile's worth and no more than two, per five miles in a route that would need double tracking?

(I left out main line railroads because it would take too long to stop and restart a long train.)

The Quincy stretch is two to three miles long. The Dorchester stretch is probably more than two miles. They’re linked by a three-mile stretch of double track. That’s too long of a stretch.

Are these two stretches what would remain after the best practical improvements, or are they just what exists today?

wicked wrote: ↑Sat Apr 01, 2023 11:06 am The Quincy stretch is two to three miles long. The Dorchester stretch is probably more than two miles. They’re linked by a three-mile stretch of double track. That’s too long of a stretch.

There is 4 miles of Single Track in the Quincy area (3.9 down to Green), and nearly 2.5 miles in the dorchester area. The VIC - SQUAINT double track is just over 2 miles.

Siding south of GREEN and GROSS are built to handle 10 minute headways for bi-directional service. Too bad you can’t get that level of service from the north end of the Middleboro Mainljne (South Station to Braintree).

Thanks for correcting me. You’re never getting frequent service Boston-Braintree until it’s double tracked. I’ll probably win the lottery before it happens. Only way there is semi-adequate service for south of Boston is if there are Braintree short turns scheduled, and given the state of the Red Line that’s a definite no go.

Middleboro is singled track from after Brockton to Middleboro. If you want increased service to NB/FB/eventually BB, you'll need to double that.

That's probably where they intend to double track under this proposal, we may see either Campello or Bridgewater Station being double tracked, if not both.

That plan would move the current junction down to near Harrison Square (where the Ashmont Line turns west). Between there and JFK/UMass, the current southbound Braintree track would become the second commuter rail track, and the northbound Braintree track would be used for widening the expressway.

I remember seeing things on here about that plan, apparently under this plan, the JFK/UMASS Braintree Branch platform would also become the station's Commuter Rail platform (meaning that it would see a realignment of the Middleborough Main, and the platform likely being extended to be 800 feet long). Since the Braintree Branch from JFK/UMass to Harrison Square would be either ripped up or converted to FRA trackage and become the Middleborough Main, this would probably also mean that the Savin Hill Flyover would be demolished. I am curious, however, as to whether the new Middleborough Main double tracking would continue for the short stretch from Harrison Square to join the currently existing double tracking that runs until North Quincy.

The Savin Hill flyover would technically be outside the construction zone, but since they'd have to close both Red Line branches during construction, It's not outside the realm of possibility that they'd remove it while they had the opportunity.

The new double track would be a northward extension of the existing double track from Quincy. It would be absurd to go to all that trouble and leave a quarter-mile stretch of single track.

Have there ever been any designs released of what a proposed splitoff at Harrison Square would look like?

The Middleboro/Lakeville line might need some track upgrades come the completion of South Coast Rail

I haven’t seen any plans to upgrade the mainline with any second track expansions. Most of the middleboro line is double tracked with the exception of campello- middleboro and montello-Braintree stretches. Idk if they could make those areas double tracked. At least plain st in Braintree is a no go since they are building a boardwalk next to it and the places I mentioned has housing next to it. In terms of track upgrades, it may be a good idea but I don’t know if they really need it. That’s a good discussion to have here though as it is getting closer to having phase 1 completed.

The row should be wide enough in all areas to support double tracking, unless MA is doing something else in the row (Red Line + Commuter Rail + Southeast Expressway choke point)

Double tracking Braintree-Montello would require relocating the platform at Holbrook.

Commuterrail1050 wrote: ↑Mon Dec 11, 2023 8:43 am I haven’t seen any plans to upgrade the mainline with any second track expansions.

There's no need to. The single-track through Quincy and Dorchester poses a hard limit on how many trains they can run. Unless and until that bottleneck can be removed, they can't increase service beyond what they already have, so there's no need for additional double track south of Braintree.

wicked wrote: ↑Mon Dec 11, 2023 4:28 pm Double tracking Braintree-Montello would require relocating the platform at Holbrook.

Ideally you could just connect the passing siding in the Braintree highlands to the double track just north of Montello. however i don't think there's enough room to widen the row going through Avon

Commuterrail1050 wrote: ↑Mon Dec 11, 2023 8:43 am IMost of the middleboro line is double tracked with the exception of campello- middleboro

West/East street siding in east/west/bridgewater