Standard Subway Tunnels vs Custom Vehicles

I've read that all new T construction is to Red Line specs. Does that include the Silver Line Seaport leg?
 
“L.A.'s cars are Nippon Sharyo...different company entirely. Japanese corporate names can be very confusing like that.”

L.A.s first batch of cars when the Blue Line first opened were from Nippon-Sharyo, however L.A.’s latest car order is from Kinki-Sharyo

http://www.kinkisharyo.co.jp/eng/e_news/e_news130731.htm

And as part of the deal, Kinki-Sharyo USA will move their headquarters from here in Massachusetts to El Segundo
http://www.dailybreeze.com/business...kinkisharyo-moving-headquarters-to-el-segundo


If LAMTA exercises all of the options, the Kinki-Sharyo cars will eventually replace the original Nippon-Sharyo cars

“Metro Rail LRV's are same width as all Green Line LRV's: 8' 8", standard PCC-like narrowbody dimension. 6 inches taller, and considerably longer @ 90 ft. vs. 72 ft. The Nippon Sharyos are old...2 batches in '89 and '94. Their latest order is from...*gasp*...Breda.”

L.A's cars are high-floor cars set up for high-platform operation.

“The Boeing dimension specs that the 7's, 8's, and now 9's are boxed into were finalized in 1973. Revisit. What's changed in 40 years of car design that offers up some flex that didn't exist in 1973? Not much?...fine. "Not much" is > zero, so quantify the options. "Absolutely none"?...I doubt it, but if that is indeed true go quantify the present-day proof that nothing is improvable from the '73 specs. That is very different than writing it off as "We've always done it this way."”

The tunnel dimensions haven’t changed since 1973. Booze-Allen did a pretty extensive review of what the options were in the early 1990s when the decision was made to go with a 70% low-floor car. LTK Engineering did a lot of work for the MBTA several years ago when the Type 9 specs were developed. The rail vehicle engineering consulting firms are hired guns that usually know their stuff pretty well. The MBTA released early versions of the Type 9 spec for industry comment and received input from the car builders before finalizing the specs that were released. Just because the final spec was ultimately for 72-foot long, 70% low-floor car doesn’t mean they didn’t review their options. Remember that the Green Line is actually pretty unique in the world of light rail operations. The number of light rail/streetcar/tram systems that operate in tunnels is relatively low world wide, a higher percentage of systems just operate on the surface. And of that smaller group of systems that do include tunnel segments, the number that squeeze modern light rail stock into tunnels built before WWII (with extensive segments built before WWI) is incredibly small. Philadelphia, Newark, and the originally Twin Peaks tunnel in S.F. are the only other U.S. light rail systems with subway tunnels built before WWII. The Badner Bahn in Vienna is the one example I can think of in Europe, most of the other tram subways in Europe were built after WWII. The clearance issues are real and they are unique.

. “Perfect generification may be impossible...it may always have to be a Boston-bred "Type _" vehicle. “

Just a reminder that the Type 8 order was the very first order placed in North America for low-floor cars (they did not end up being the first delivered because of the delays with Breda). The MBTA was a leader in car design at that moment, but got burned because the winning bidder was not up to the task. The losing bidders for the Type 8 contract in 1995 were Kinki-Sharyo, Siemens, and Bombardier. Kinki-Sharyo’s proposal in 1995 for their version of the Type 8 became the basis for the car they would build for New Jersey Transit, except that the New Jersey cars were longer and did not have front doors. We might have a very different opinion of what the state of the Green Line is today if history had been different and Kinki got the Type 8 job. The specifications the MBTA has put together for the Type 9 look like it could potentially be a very solid car, but they have to commit to spend the money to buy them. They have been sitting on the bids for the small 24 car order for GLX for about two years now. By necessity, the Red and Orange car procurement is going to be a higher priority and a revamped Green Line fleet might have to wait awhile. At least the Type 7 overhaul program is underway
 
I've read that all new T construction is to Red Line specs. Does that include the Silver Line Seaport leg?

Yes. T buses are 102" wide, Red Line cars 122" wide. Add the fudge factor of steering a rubber-tire vehicle inside a tunnel and you get a tunnel easily that wide or wider and turning radii much gentler. Height not an issue in that tunnel either since the trolley poles have pretty generous clearance.

Red Line / NYC Subway B-division dimensions are the most common in the world. Unless it's a specific design choice to start from the ground up with a wider footprint (BART, D.C. Metro) that's pretty much been the de facto world standard for 100 years now.

That's not to say you can drive a Red Line car through every single piece of tunnel built after 1920. You most definitely can't send one down the Science Park portal and wrong-rail it inbound on the 1963-construction side into the middle of the loop. The turning radius was never designed for that. But it's been an engineering default to set the physical width/height of any new metro rail tunnel to the NYC standard and work from there. For the same reason as buying generic-dimension trains when you can...less design customization required, more expertise to shop around for at building a generic-dimension concrete thing. Think about it...if you had a metro rail tunnel project that required a tunnel boring machine for one segment, would you ask for a custom-built TBM to bore to your unique-as-a-snowflake dimensions or use a standard-size bore? There has to be an exceptionally unique and ironclad reason not to go with some standard-size bore for what extra that would cost. So they tend not to stray from the defaults anywhere with a new-construction tunnel if they can help it.
 
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