The Orange Line Thread

Back when I toured the OCC, I asked about new OL rolling stock and a possible timeline. The woman that was giving us the tour said that ATO was the primary priority on the entire line and once it was installed, the T was going to place an order for new rolling stock.
 
Matthew said:
It automates certain parts of the train operation, e.g. starting and stopping. In some systems it can entirely substitute for a driver, in others the human is still required to do some things.
Click to expand...

Will this enable shorter headways if/when the new trains arrive? Copenhagen Metro employs ATO on all lines and they have 2 minute peak headways on the most heavily used portion (it appears to be only 2 tracks even though it serves 2 "lines"). Would there be any other obstacles for shorter headways on the Orange Line other than purchasing new equipment?
 
The length of the blocks would be the main obstacle to shorter headways on the Orange Line. I'm under the impression that the signal system currently installed can support headways of 5 minutes (and possibly better) so the main problem there is the lack of cars.

Other block signal systems have been designed for headways as short as 2 minutes, I've even heard of 100 seconds, but not any of ours. It mostly depends on the stopping distance of a train travelling at speed, plus an added safety padding factor. The static block system can be thought of as an overestimation which ensures the separation is always greater than the stopping distance.

Copenhagen is fully automated, I believe. ATO runs the train according to a schedule and interprets the signalling, but is not ultimately responsible for the safety of the train. They usually call that something like ATS, a system which can stop the train if it exceeds the safety margins.
 
Copenhagen is completely driverless with full automatic train control (protection, operation and supervision).

From the sounds of it, the Orange Line upgrades will bring the whole line to a semi-automatic Grade of Automation; we'll still have the fixed-block system and the train operator would still handle opening/closing doors and initiating train acceleration. I believe this is what the Red Line has? Didn't realize the Blue Line is still on an ABS system...
 
Huh?! I thought the Orange Line signals were already upgrade in the Haymarket-North section back in the late 90s and early 2000s? I remember it ground on for YEARS! And the result was ATO, but functioned only as ATC (driver still controls everything, signals merely incur brake penalties for excessive speed). So was all of the grueling pain of years of signal work just a decade ago all for nothing?
 
The capital plan references Chinatown-Oak Grove as the segment that will be upgraded. It does mention upgrades made to the Green Line on Haymarket-North Station when they did the huge rebuild, bu no mention of the Orange Line.
 
The Orange Line Signal System upgrade has already been completed. The project is still in the capital plan to account for closeout costs. Look at the chart on page 73 of the present draft capital plan (linked previously). The total cost for the Orange Line North Signal Upgrade project was $80.20 million, and the only money left to spend is $4.93 in FY 2014.
Almost complete projects remain in the capital plan as long as there are still open claims from contractors that have not been closed out.

The present peak schedule on the Orange Line is 5 minute headways. The signal system can now handle service at least every 3-4 minutes. More equipment is needed to run more trains. The plan is to buy 152 new cars to replace the present 120 car fleet. During the rush-hour, 96 of the 120 cars (16-trains) are required to meet the peak requirement. The other 24 cars are in maintenance. Floor repairs has been a major issue for the fleet for the last few years.
 
^ Thanks for that info! Clear, concise, and to the points.
 
Matthew said:
It automates certain parts of the train operation, e.g. starting and stopping. In some systems it can entirely substitute for a driver, in others the human is still required to do some things.
Click to expand...

The old signal system Haymarket-north was an old-school mechanical trip arm system like the Blue Line has. Everywhere south of there was the same solid-state ATO system the Red Line has where stops and speed limits are auto-enforced through a 1-bit electromagnetic pulse through the running rails that the train picks up. The construction project that finished about 5 years ago finally got the whole OL on the same system and removed a lot of maintenance-intensive mechanical parts.

ATO is a 'dumb' system in that it's an analog signal, has no two-way communication (signal is dispatcher-to-train only), and still relies on fixed signal blocks which can lead to congestion and bunching (i.e. trains stopped in tunnels) at individual blocks. CBTC, the newest kind of signal system, is digital, 2-way continuous communication, computer-controlled, and can be set up to allow moving blocks governed by safe distance between trains to substantially increase headways (note: while there's concern about its effectiveness on light rail headways in the recent Green Line report, it is proven tech for realizing that upside on heavy rail. Especially lines as relatively simple as Red/Orange/Blue.

The Haymarket-north ATO project did trench all-new fiber cable for the new signals, meaning the trunk feed has got more than enough bandwidth to support a CBTC upgrade later. You just replace the trackside ATO signal repeaters that send the signals through the running rails with their CBTC equivalents (and likewise with the onboard equipment), and use the same fiber feed hooked up to the new system. It can even fire both signal systems simultaneously if there needs to be an overlap period while they transition over. It was laying all those utilities that sent the project years late and millions overbudget, so thankfully they'll never have to do that again. Haymarket-south, however, does require a complete rip-out/replacement of all the circa-1987 copper signal wire. They can't replace the ATO down there without laying fiber. And that's a huge frigging expense. Thankfully, they can lay the fiber and run the existing ATO on it before they start rolling out CBTC, so it's a project they can accomplish in stages.
 
Since I don't know where else I'd put this...

I found this map on Reddit just now from 1948.

hF8w2ng.jpg


If you look closely you can see an authorized rerouting of the Washington St elevated along a subway under Shawmut Ave from Dover St to Dudley Sq. I had heard of the desire to do such a thing but I had no idea it was approved.

Anyone have any more info on this?
 
This is mine! Bought it off ebay. I figured since this is the first map published under the MTA they might of been showing off some ideas?
 
That is an awesome map. I actually remember seeing that map posted on the station walls when I was a kid, including the proposed Shawmut Ave subway. Damn, I wish they had built that.
 
I'm pretty sure one of the original prints of this is in the transit library at Park Plaza. But I never noticed the Shawmut subway on it. It could be that it was actually a different map.
 
This map was updated every few years, so there were different versions. I have a scan of an earlier version of the map that does not show the Shawmut Ave subway proposal. The MTA updated and published the map until the MTA was abolished in the mid 1960's.
 
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I have the system expansion map from '47 that predated every project 30 years later but I never saw the Sawmut Ave subway which is why I asked.

Charlie_mta said:
This map was updated every few years, so there were different versions. I have a scan of an earlier version of the map that does not show the Shawmut Ave subway proposal. The MTA updated and published the map until the MTA was abolished in the mid 1960's.
Click to expand...
 
I'll post my MTA maps on here when I do a scan this week of the hard copies I have.

They are of the same type as the one you posted, but are different versions issued in different years.
 
It also looks like a new parallel tunnel was authorized for Tremont St between Park St and Scollay Square. Anyone know anything about that?
 

BERy - Green Line by vanshnookenraggen, on Flickr

The section from Gov't Center to Park St is a choke point since it wasn't designed with modern commuters in mind. Basically all trolleys from the north terminated at Scollay Sq (or Adams Sq) and all trolleys from the south at Park St with a few going through. Then the subway changed how people commuted and they had a choke point.

This would have created a very spread out Gov't Center station as the northbound platform would be a couple blocks away from the southbound. Not sure what the plans were for Adams Sq station at this time.

Also if you look closely they would have combined Park St and Boylston St with two giant super platforms. Not sure how exactly this would be a benefit. Maybe transit planners were toying with this idea back then since the Chicago subways have this feature as well.
 
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