BostonChicken wrote:aline1969 wrote:That looks pretty good, I like the Type 7's in Boston who are built by this company. I like this for the type 9 
I like the Type 7s as well but this ameriTRAM seems like it would need heavy modification to work here. The specification http://www.ameritram.com/pdf/ameriTRAM_Brochure.pdf says it has a minimum turning radius of 60' which isn't sufficient for the Boylston curve, AFAIK. Just from looking at the pictures it doesn't seem like it would handle it, either, only two bogies on the 300 model? Also, I'm not a fan of the omnibus style seating.
Park St. loop is the minimum-radius curve on the Green Line that sets the spec for the T's orders (42 ft.). Inner loop at Lechmere yard is also a tighter one, but that's going away in 4 years when the station gets moved. Boylston curve is a bit wider than those loops. How much so, I don't know, but Park loop is 5 MPH restricted and Boylston curve is at least twice that speed. Park loop is not used for revenue service except as-needed when a train (usually B line) blows a schedule badly and needs to get its run aborted before it goes through the Park-Government Center congestion and screws everything up worse. That practice is going to end by 2014 because they're installing a new crossover that finally allows the inner inbound track to get used for thru service to Government Ctr. With 2 tracks available that means scheduling will wave ahead the train that has the greater need of getting there first. Usually that means a North Station or Lechmere train that needs to get ahead of GC-turning trains to the far end of the platform, but it'll also mean a late train that would otherwise get aborted at Park can get priority in the queue to GC and finish its run without further delays. They're building it because it substantially increases the throughput to support the northside extensions they're building and substantially improves schedule-keeping (also only costing $3.2 mil to do). But it will also end use of Park loop except for out-of-service deadheads and flukey service disruptions.
The loop can go away without compromising operations. They can throw down a switch from the inspection pit track to the outbound side to reverse ends on (at least single units, not sure if it's long enough for doubles) in the event something breaks down. When the extensions are built the north end of the subway will have a maintenance yard for the first time in its history, which also means disabled trains are going to deadhead there (maybe with layover at North Station yard to avoid fouling other trains' schedules) instead of reversing direction and going way out west to Reservoir or Riverside yards. Honestly, if you weigh the cost of perpetually over-customizing car makes vs. need for keeping in service a soon-to-be depreciated 19th century loop...get rid of the loop and let Boylston be the minimum-radius arbiter. If that closes the gap between 42' and 60' and gets you at or close to the halfway point, that's a whole lot fewer mods required to an off-the-shelf model to get it running in Boston. And avoids in-total the kind of ridiculous over-design that made the Bredas such a cost and reliability debacle.
