Saturday, June 27, 2009

Saturday Sacramento Links

It was nice to see everyone at the NJudah shindig last night. I'm in Sacramento for a family reunion this weekend so posting might be light.

Looks like Phoenix is pausing its first extension due to funding issues.
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I think people like Barbara Boxer still don't get the climate, transport, land use connection. I am glad that folks are talking gas tax, but there has to be a better way.
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LA is building an Orange Line extension that connects the Chatsworth Metrolink station to the Warner Center, which is kind of like LA's Tyson's Corner. I think this is a great connection that obviously should be updated as soon as possible. With the Warner Center thinking about densifying, the connection to commuter rail is key.
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I like this quote from Rep. John Mica:
"if you're on the Transportation Committee long enough, even if you're a fiscal conservative, which I consider myself to be, you quickly see the benefits of transportation investment. Simply, I became a mass transit fan because it's so much more cost effective than building a highway. Also, it's good for energy, it's good for the environment – and that's why I like it."
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Some interesting information on traction motors in Europe. Kind of continues on our electrification theme of late.

7 comments:

Bob Davis said...

Oh for the days when most traction motors bore the logos of General Electric or Westinghouse. There are still quite a few around, but most of them are in museum cars and locomotives. I've been "up close and personal" with some of these relics, having helped install, maintain and repair them at Orange Empire Ry. Museum. (There are several thousand GE traction motors in main line locomotives, but not many in transit cars.) There was a brief mention of a "gearless" motor, which sounds like something for "hub drive" wheels in low floor cars. This idea (in a somewhat different form) goes back over a hundred years, when some cars had the armature built on the axle and the motor case and field windings bolted around the armature. It eliminated gears, but was a maintenance headache, so the design didn't last very long in transit operations. The concept did catch on for main line locomotives, where floor levels weren't a major design consideration.

Anonymous said...

The Orange Lie thing is dumb, long term make this a commuter rail line!

Matt Fisher said...

Anon.,

I wish it were, too.

njh said...

Bob Davis: The main reason to avoid gearless drives is the added unsprung mass which makes for a bumpier ride. That has been the killer of the idea for the last 100 years. Once the motor masses less than the gear though, the problem is solved, which I think is their claim. Electric cars solve this problem with a diff or flexible coupling. However, the forces involved in a train bearing make this impractical.

I've wondered whether there has been much effort in reducing the mass of train wheels, perhaps using a spoked arrangement, it seems to me that this is easiest way to reduce unsprung mass.

arcady said...

I've definitely seen spoked wheels on trains, specifically on the trailer cars of MU trains in Russia. The problem with wheels is that they have to be strong enough to bear the weight of the train and withstand impact forces from joints and flats, and strong enough to withstand the torque from motoring or braking. They also have to have a tread of reasonable thickness because tread brakes wear down the tread, and even if there aren't any tread brakes, the only way to make a wheel round after it gets uneven is by cutting away metal until it's round again. There have been all sorts of attempts to at least reduce the unsprung weight though, for example the PCC streetcars have a two-part wheel, where the tread bolted to the rest of the wheel with a rubber cushion between the two.

Bob Davis said...

Spoked wheels have been used in various applications; probably the most obvious is steam locomotives. Pacific Electric used spoked wheels on their home-brew freight locomotives for many years, but went to solid wheels at the end. The sole survivor of this group has solids, but a photo from 1943 appears to show spokes. Orange Empire Ry. Museum has an Irish tram that's now over 100 years old with spoked wheels; it could be they were more common in overseas tram operations. Horsecars probably had spokes--the less "iron" Old Dobbin had to haul around, the better, but that's not a very stressful application for the wheels. There could be manufacturing considerations that make solid wheels a better choice for modern conditions.

njh said...

Doh! I forgot about steam train wheels being spoked. Perhaps it is best to avoid the spokes and go for a foamed metal or similar. (Never trust a truss, my friend says) Aluminium wheels (with steel tyres)?