interchangeability??

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interchangeability??

Postby RFP » Tue Dec 13, 2016 7:19 pm

I hardly ever post to avoid dumb questions but as I was reading about ordering red line cars et al today a dumb question surfaced. Why can't a universal train be ordered to run on the blue, orange and red lines? I know that red/blue/green/orange all have the same width track. Here goes..... If the track is not an issue I assume ?? that the other things to consider are tunnel clearances and power requirements. Surely, if tunnel clearance is an issue than the smallest universal car would be a fit for all. If power type of stuff is the sticking point can't the train have the ability to "shift" to the appropriate power requirement. It can't be this simple but if this kind of flexibility can be added the benefits are numerous and the maintenance / parts issues becomes much simpler and more economical.. Now, that I've been so simplistic, will someone pls set me straight? Thanks......
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Re: interchangeability??

Postby Disney Guy » Tue Dec 13, 2016 7:34 pm

For starters, (1) Platform heights are different (Blue line is somewhat lower), (2) width of the cars at platform level are different. (3) The smaller (narrower) Blue Line sized cars on the Red Line would reduce the passenger carrying capacity when we are trying to increase that.
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Re: interchangeability??

Postby csor2010 » Tue Dec 13, 2016 7:44 pm

Tunnel clearances and platform heights are the main reasons that I'm familiar with. Size-wise, Red > Orange > Blue, with Red Line cars being the widest and Orange Line cars being longer than Blue Line equipment. RL car length is set by the Harvard curve, the OL is height-limited by the dip under the Blue by State and width-limited by the Washington St. tunnel, and the BL cars are length-constrained by the Bowdoin loop. Going off tunnel clearance alone, you could theoretically run a Blue line train on the Red, but you'd be wasting tons of capacity by not filling up as much tunnel space as possible. As Disney Guy said, Blue Line platforms are also lower and the cars have the added requirement of pantographs. This article has some details on the exact platform heights and car lengths.

Now, you can get a fair amount of benefit by platforming the cars off each other - the BL 0600s and the OL 01200s had a lot in common and did share a large number of parts. Someone else can probably give more detail, but I've heard that there were plans to salvage the 0600s for extra OL capacity when they were displaced by the new equipment, but the combination of having to alter the car height and the advanced state of salt rot on the bodies prevented that from being feasible. Likewise, the new Red/Orange equipment will share as many parts as possible.

All told, even if you did have universal equipment it would be of dubious use given that there is no track connection between any of the rapid transit lines.
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Re: interchangeability??

Postby ns3010 » Tue Dec 13, 2016 8:24 pm

The most significant problem is car width. The OR/BL cars are narrower than Red, which means you would have to redo all of the platforms on at least one line depending on how you would be standardizing. Car length is another issue, but less critical. The car lengths actually work out that an 8 car train of BL stock would fit on OR platforms, but then you're also buying a ton of cars with unnecessary equipment (pans).

With the height, width, and length incompatibilities, and of course the lack of connections between lines, means that there will never be any interchangeability between lines. Unfortunately, a series of poor decisions in the past that can never be corrected.
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Re: interchangeability??

Postby Aerie » Tue Dec 13, 2016 8:46 pm

Remember that the Tremont street (Green Line) subway was the first built in 1897, and was built for trolley cars. When the Boston Elevated (Orange Line) was first built, it was routed through the Tremont Street subway until the Washington Street tunnel was built, so the elevated cars had to be the same width as the trolley cars. The East Boston tunnel (Blue Line) was also originally built for trolley cars. Only the red line was purposely built as a heavy rail line.
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Re: interchangeability??

Postby NRGeep » Wed Dec 14, 2016 7:34 pm

Are there any other cities that have such a wide variety of non interchangeable urban rail?
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Re: interchangeability??

Postby Backshophoss » Wed Dec 14, 2016 11:28 pm

NYCTA,the older IRT lines are a bit smaller then the BMT and IND lines.
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Re: interchangeability??

Postby typesix » Wed Dec 14, 2016 11:36 pm

New York, according to Wikipedia, has two separate fleets of incompatible cars for their IRT and BMT/IND routes. The BMT then also has some lines where only certain classes are allowed due to curves or length.
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Re: interchangeability??

Postby NorthWest » Thu Dec 15, 2016 12:40 am

SEPTA's Market-Frankfort Line and Broad Street Line aren't even the same gauge, let alone loading gauge.
Add in PATCO (which has now-disused connections to the Broad Street Line) and you have a third fleet of cars.
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Re: interchangeability??

Postby Bramdeisroberts » Thu Dec 15, 2016 9:26 am

NRGeep wrote:Are there any other cities that have such a wide variety of non interchangeable urban rail?


Lyon springs to mind, where they have two lines running interoperable fleets of rubber-tyred Paris-style metro cars, one completely automated line running driverless rubber-tyred Paris-style trains, and one line running two-car rack-and-pinion vehicles with caternary electrification.

As for the Western Hemisphere? Only Philly comes close to the T's "4 lines, 4 different fleets" situation.

And with ITT/BMT+IND standardization, remember that each individual sub-system is over twice as large as the T. It's hardly a case of "fleet incompatibility" when each of your two individual fleets are larger than all of CTA's.

Compare that to the Blue Line, where 8 miles of track and barely 10 stations necessitates its own, completely incompatible fleet!
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Re: interchangeability??

Postby nomis » Thu Dec 15, 2016 9:32 am

The Greater Philadelphia area currently have 6 non-railroad compliant (or wavered i.e. Riverline DMU's) transit vehicles, PATCO, BSL, MFL, City Trolleys (with tunnel running), Suburban Trolleys (double ended, and do not fit in the tunnel), and NHSL "Norristown High Speed Line". The BSL, PATCO (now different DC voltages with severed connections), and NHSL are all 4' 8-1/2" standard gauge. The others are prescribed to have Pennsylvania Trolley gauge at 5' 2-1/2" for the Suburban Trolleys, and Philadelphia gauge of 5' 2-1/4" for the MFL and City Trolleys.
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Re: interchangeability??

Postby ExCon90 » Thu Dec 15, 2016 4:13 pm

Los Angeles has some claim to fame in that it has the Red-Purple Line (standard heavy-rail), Blue-Expo Line--and Gold Line, without physical connection to the Blue-Expo, (standard light-rail), Green Line (standard light-rail with automatic train operation and no grade crossings), and Orange Line (busway with grade crossings), all done within a relatively short time under the same management. There was a newspaper report at the time the Green Line was being designed that the planners pointed out to the then-mayor that ATO was unnecessary in the circumstances, and the mayor said that ATO was the best technology available, and "LA must have the best."
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Re: interchangeability??

Postby jonnhrr » Wed Dec 21, 2016 2:58 pm

London like NYC has 2 different loading gauges, the subsurface lines (District, Metropolitan, Hammersmith and City, Circle) which were originally build to steam railway standards (and actually ran with steam power originally) and the "tube" lines which are smaller as they were early deep tunnels. Then there is the Waterloo and City which is a short 2 station shuttle between 2 key stations that has its own unique equipment. So different lines built to different loading gauges seems to be pretty common in the mass transit field, especially systems that have been around a while and with pieces built by different companies.

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Re: interchangeability??

Postby mgdemarco » Wed Dec 21, 2016 3:35 pm

Was there ever a connection between any of the rapid transit lines?
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Re: interchangeability??

Postby jwhite07 » Wed Dec 21, 2016 6:07 pm

Was there ever a connection between any of the rapid transit lines?


Kinda-sorta. Beyond Bowdoin on the Blue Line, the track (remnants of when the East Boston Tunnel was a through route for streetcars between Cambridge and East Boston) surfaced onto Cambridge Street and proceeded through Charles Circle and over the Longfellow Bridge, joining the Red Line tracks to Harvard Square. This was non-revenue track, used when the East Boston Tunnel fleet was maintained at the Cambridge-Dorchester line's Eliot Shops near Harvard Square, before the Revere Extension and Orient Heights Carhouse was built. Once Orient Heights was opened, the "back door" beyond Bowdoin was sealed and the track connection ripped up.

There were also a few places where the streetcar and rapid transit systems were connected, including a (I believe still extant) connection between the Mattapan Line and the Red Line near Codman Yard at Ashmont. After the Mattapan Line became orphaned with no connection to the rest of the streetcar system and no carhouse of its own, PCCs requiring major maintenance or repair would be coupled using special coupler adapters and towed behind Cambridge-Dorchester trains to Eliot Shops during overnight hours. After Eliot Shops were closed and torn down, PCCs have been trucked if necessary to repair points such as Riverside or Charlestown.

To my recollection there have never been any physical connections between what is now the Orange Line and either the Blue or Red lines, although I do recall seeing the pre-production Blue Line 0700 cars undergoing testing on the third track between Sullivan Square and Wellington on the Orange Line, and I believe some Orange Line 01100s did a stint in work train service on the Red Line for a brief time. Obviously non-revenue, obviously trucked there.
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