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MBTA says this time, no really, honest, for reals, it's fixed an infamous Orange Line slow zone between Tufts and Back Bay

The T, which said it was going to fix the long-running, high-squealing slow zone between Tufts Medical Center and Back Bay when it shut the whole line for a month last year, said yesterday it's actually fixed the problems along the tracks, and this time it means it, Streetsblog Massachusetts reports.

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From the linked article last year:

Baker acknowledge more work needs to be done on the T, but credited himself and his administration for getting the T into a better position, after decades of it being underfunded by previous governors. He said the T's backlog of unfunded capital projects has shrunk from $12 billion to $6 billion and that even with its superannuated cars and tracks, on-time performance now is better than when he took office.

What a sham.

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confirmed that there was, indeed, a problem!

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He needs to be confronted with this reality wherever he goes.

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The Tufts approach tunnel will always have some kind os slow speed restriction on it due to the nose forces applied by a fully loaded train on a combined down slops and curve as it enters the tunnel.

Part of the problem was the build out of the tunnel that parts off Washington Street and skirts the foundation of the Double Tree Hotel. That area was set for construction and development long before the Orange Line plan was even started to abandon the steel elevated. That segment of the tunnel and what would become Tufts Station was built a full 10 years before the rest of the Orange line to back Bay would be created.

This gave engineers few options for connecting the Orange Line at Back Bay, which followed the standing rail right-of-way, with a steep and curved tunnel approach passing under the end of the Mass Pike.

A loaded train traveling down (inbound) places stress on the outer edge of the rails as it descends and turns left. This stress will, over time, wear the outer rails as well as the supports to the rail ties. On the outbound side the stress is similar pulling back (downward).

Derailment threat requires passing this area at a slower speed to reduce the stress. The curve is also acute usually causing wheel whistle (that screech of the wheel sound) as the wheels press against the steel rails.

So even if they managed to get a slight speed increase, it is physically impossible to take that downward curve at speed.

The only fix would be to change the geometry of the incline and acuteness of the curve. That would be a "big dig" like project that would shut off the commuter rail, Mass Pike, and the Orange Line for months if not longer. The challenge faced "back in the day" was not ideal by any means but that gave us public transit.

So when it slows down again, don't flip off. It will in fact happen again.

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