|
Podima posted:As a non-CT resident who drives there pretty regularly (fiancee's from West Haven), what the heck is it with the stretch of 95 leading up to Exit 14-15 from either direction? It's ALWAYS backed up, and I have no idea why - the minor amount of construction going on there isn't nearly enough to produce the level of traffic that I see on a regular basis.
|
#
?
May 28, 2013 23:10
|
|
|
|
| # ? May 12, 2024 18:12 |
|
|
Cichlidae posted:Here's some food for thought: what if gas prices suddenly rose to $100/gallon? Granted, it'll never happen (at least not all at once), but imagine prices hit that peak tomorrow morning. How would your life change? Telecommuting would be nice, but those of us in the service industry would be completely hosed over.
|
|
#
?
May 29, 2013 16:16
|
|
|
Cichlidae posted:Here's some food for thought: what if gas prices suddenly rose to $100/gallon? Granted, it'll never happen (at least not all at once), but imagine prices hit that peak tomorrow morning. How would your life change? Living out of a pick-up truck because I'd be working 18 hours a day at Ft. McMurray. I'd be buried with my millions at 29.  Saying that a lot of people would buy little electric cars for their commute. Cost of food would skyrocket though. That would be a huge problem.
|
|
#
?
May 29, 2013 16:57
|
|
|
Sovy Kurosei posted:Saying that a lot of people would buy little electric cars for their commute. Cost of food would skyrocket though. That would be a huge problem. It is a lot cheaper to buy a 2 cylinder gas car and draft behind a truck at 85 kph. We would probably see people drive a lot slower. The past few years i see more and more people who are not driving at the speed limit or even slightly below it. 110 kph vs 130 makes a big difference, my car seems to be most efficient from 70-90 kph where ~3.5L per 100km is possible, at 130 kph this increases to ~6.5L per 100km.
|
|
#
?
May 29, 2013 17:20
|
|
|
I wanted to show you guys some lane continuity diagrams, but I've been sick as a dog these past few days. Once I recover, you'll get some nerdtastic stuff. Also, person with whom I've been extensively communicating via PM, your inbox is fuller than my barf bucket.
|
|
#
?
May 29, 2013 21:21
|
|
|
Varance posted:The agency I work for is switching to CNG. Diesel is a terrible fuel for transit now that SCR systems are required and increase breakdown rates fourfold. Interesting, I wasn't aware of the DPF regen being an issue in city driving conditions. Now that we have a number of DEF-using consumer diesels on the market do you see this becoming a problem for vehicles that are primarily city driven? I agree entirely that electric is the endgame for transit, its such an ideal solution given the predictable range requirements and effectiveness of regenerative braking. Big, roughly squared off buses would also seem to be the ideal sort of vehicle for the often discussed idea of standard, swappable batteries which would allow a fleet to have a rapid "refuel" stop while recharging the batteries at a more reasonable rate for both cell life and power wiring constraints. I wouldn't be surprised to find that current battery technology can provide an acceptable range for many routes if the battery modules were able to be swapped in a matter of minutes rather than requiring a vehicle to go down for hours to charge, so at that point it becomes a matter of price. On paper electric should be much more reliable simply due to reduced moving parts to fail, though obviously in practice some of the hardware isn't as mature as we might prefer.
|
|
#
?
May 29, 2013 22:04
|
|
|
A lot of the buses here are transitioning to hybrids or bio-fuel stuff, not sure how much better it is. Vancouver has a LOT of electric buses though.
|
|
#
?
May 29, 2013 22:08
|
|
|
Ah yes, the trackless trolley, my old nemesis.
|
|
#
?
May 29, 2013 22:10
|
|
|
So pissed I didn't ride one of those when I was in Vancouver.
|
|
#
?
May 29, 2013 22:35
|
|
|
They're nothing exciting, well unless the pantograph falls off then the driver gets out with a big long stick and sticks it back on.
|
|
#
?
May 29, 2013 22:47
|
|
|
I get in a lot of local slap fights over transit modes on a local forum I'm a member of, and I'd like to have some first hand experience on the ride quality of an electric rubber wheeled vehicle.
|
|
#
?
May 29, 2013 22:53
|
|
|
It's exactly like a normal bus, exactly. Other than the sound of the engine the ride is the same, maybe a tiny bit smoother?? Driver skill is still a way bigger factor than the engine type in this situation though.
|
|
#
?
May 29, 2013 23:03
|
|
|
FISHMANPET posted:I get in a lot of local slap fights over transit modes on a local forum I'm a member of, and I'd like to have some first hand experience on the ride quality of an electric rubber wheeled vehicle. The electric buses in Copenhagen (battery-driven, no overhead wires) aren't very interesting. I've only used them twice or so, from how I remember last time somehow it was still vibrating a lot. On the other hand, a hybrid test-model they had on another route, was really comfortable when it was running only on battery, no horrible vibrations while stopped and obviously no motor noise. Unfortunately it very rarely turned the fuel motor off, making it not as great as it could have been.
|
|
#
?
May 29, 2013 23:06
|
|
|
We've got a lot of Gillig hybrids in our fleet, but they pretty much drive like regular diesel busses. However, I had the good fortune to ride this bad boy: http://www.metrotransit.org/xcelsior.aspx, and that was pretty fantastic. The hybrids we have right now have the engine running all the time to power the internal cabin stuff, and I don't think it changes the acceleration profile very much compared to standard diesel. But this new bus does actually turn the engine off, so every time we pulled away from a stop it smoothly glided out rather than lurching as the transmission shits gears on a traditional bus. So I was wondering if an all electric bus has a different acceleration profile pulling out of a stop than an internal combustion engine powered vehicle.
|
|
#
?
May 29, 2013 23:16
|
|
|
Yeah, electric buses tend to accelerate a bit smoother, but a good driver is going to be smooth in either vehicle and a lovely driver is going to be jerky.
|
|
#
?
May 29, 2013 23:23
|
|
|
FISHMANPET posted:So I was wondering if an all electric bus has a different acceleration profile pulling out of a stop than an internal combustion engine powered vehicle. I can't speak to how it applies to buses, but one of the big differences between electric motors and IC engines is that electric has a more-or-less constant torque output throughout its whole range, whereas an ICE generally has a hump somewhere in its rev range. So with an ICE vehicle, you're changing gears to spend as much time as you can in the hump, but with an electric motor you're always there. For something low-speed like an electric bus I wouldn't be surprised if they ditched a transmission entirely (outside of differentials and stuff if you're not giving each wheel its own motor).
|
|
#
?
May 29, 2013 23:26
|
|
|
Yeah, a hybrid that only turns the fuel engine on after being up to speed is wonderful, but it doesn't work well in stop-and-go traffic, or with short distances between stops. Otherwise the battery simply doesn't get a chance to recharge sufficiently, and then you get idling with the fuel engine on.
|
|
#
?
May 29, 2013 23:26
|
|
|
Vancouver transit Goon here! The electric trolleys have slower acceleration than the diesel buses, but aren't impacted by the grade of the road. The trolleys are most commonly used in the busy stop-and-go traffic, so it's not that big of a deal. They also sound cool.  Where you notice the difference is if you want to climb a hill. Where a diesel bus would crawl up it, engine at max RPM the electric trolley climbs that like no big deal. Also yes when the bus operator screws up is always fun to watch. The buses are designed to pull their poles off the wire if any sort of fault happens, be it operator error or anything else. If an operator makes a corner badly, they'll spark and lower themselves, leaving the bus in the intersection making everyone angry. Vancouver's trolleys have battery backup, allowing them to drive a short distance to get out of the intersection or to a safe stopping area where the operator can get out and link the poles back onto the wires. Vancouver trolleys can't use pantographs, because two wires are required above, unlike 1 wire in LRT and other rail applications. Because there isn't any rail below the vehicle, a 2nd wire is required for grounding. And when I said the buses are designed to pull their poles, that's because damage to the overhead wire would cause a much bigger problem than a broken bus. Even if it means losing the assembly and a $100,000 repair.  
|
|
#
?
May 30, 2013 00:17
|
|
|
Ah when there is only 1 wire it's not called a pantograph anymore? Just what.. a pole?
|
|
#
?
May 30, 2013 00:27
|
|
|
Baronjutter posted:Ah when there is only 1 wire it's not called a pantograph anymore? Just what.. a pole? When it's just a pole, it's just a trolley pole. It doesn't have to do with how many wires are up there.  Trolley pole   Pantographs The key feature of a pantograph is that it has a pantograph construction, a mechanical linkage system that operates in the manner of an old-time pen pantograph:  Obviously the older style full diamond looked a lot more like it then the current half diamond designs popular nowadays. Pantograph designs typically allow for much more stable connection at high speeds and when dealing with collecting power from wires that may have variable height. Nintendo Kid fucked around with this message at 00:51 on May 30, 2013 |
|
#
?
May 30, 2013 00:45
|
|
|
Install Gentoo posted:Pantograph designs typically allow for much more stable connection at high speeds and when dealing with collecting power from wires that may have variable height. That said, when a panto breaks/slides off the wire at high speed and the auto-drop fails, the damage can be catastrophic (whereas a trolley pole will just snap in most cases). Varance fucked around with this message at 01:11 on May 30, 2013 |
|
#
?
May 30, 2013 00:58
|
|
|
Baronjutter posted:Yeah, electric buses tend to accelerate a bit smoother, but a good driver is going to be smooth in either vehicle and a lovely driver is going to be jerky.
|
|
#
?
May 30, 2013 01:23
|
|
|
I really need to start a separate thread for transit, one of these days. All-Electric buses have torque as their strength. They work on the same premise as diesel locomotives, sending power to motors that directly turn the wheels, no transmission involved. They accelerate at about the same rate, regardless of the grade. This makes them AWESOME for cities like Vancouver and Seattle with hilly terrain. Advances in battery, engine and charging tech will eventually allow All-Electric buses to go wireless and become the standard flavor of transit bus, with prototypes currently in operation around the world. Diesel-Electric Hybrids come in two flavours: Serial and Hybrid. If the engine runs constantly, you're riding a "serial" hybrid. The vehicle is driven solely by an electric engine and functions almost exactly like an All-Electric vehicle, with an engine in the back that functions as a generator (usually something small, like a pickup truck Cummins ISB). Serial hybrid buses are badass for urban stop-go traffic, where you'd see tons of power regenerated via braking. Since the electric engine is doing everything, the diesel must remain operational at all times to provide power. If the engine shuts off at all, it's a "parallel" hybrid. Both the ICE and electric motor are attached to a traditional drivetrain, with the engine turned off while coasting. Parallel hybrids are best suited for freeway/express service, as that's where you'd see the most benefit. Parallels usually use a heavier Cummins ISL engine, same as the average diesel transit bus, resulting in lower fuel economy. The ICE will do most of the heavy lifting during acceleration, after which the engine will completely shut down while coasting down a highway. In simpler terms, serial hybrid buses are like freight train locomotives, parallel hybrids are like the average hybrid car. And that's exactly how each drives. Of course, the driver determines how smooth your ride is, not the engine/vehicle design. A lovely driver will make even the best of vehicles ride like poo poo (slamming on brakes, etc). ---------------------- For those wondering exactly how much fuel is being saved, the best in class fuel economy for a 40 foot bus is about 5.5 MPG, from New Flyer's Xcelsior as a serial hybrid. Best in class for a parallel is 5 MPG, also from the Xcelsior. The average 40 foot transit bus is around 2.5 MPG. Cutaway buses (the van looking things) are usually around 10 MPG, varying based on size and engine type. Also, there's one special case of hybrid: SEPTA's New Flyer E40LFR All-Electric buses are super hybrids - they can run from trolley overhead, batteries OR a diesel engine. If there's a detour on route, the driver can lower the poles and activate the diesel engine to drive off route, then switch back to overhead operation after the detour. Varance fucked around with this message at 02:19 on May 30, 2013 |
|
#
?
May 30, 2013 01:40
|
|
|
Varance posted:If the engine shuts off at all, it's a "parallel" hybrid. Both the ICE and electric motor are attached to a traditional drivetrain, with the engine turned off while coasting. Parallel hybrids are best suited for freeway/express service, as that's where you'd see the most benefit. Parallels usually use a heavier Cummins ISL engine, same as the average diesel transit bus, resulting in lower fuel economy. The ICE will do most of the heavy lifting during acceleration, after which the engine will completely shut down while coasting down a highway. A small nit to pick here, but a parallel can run without turning the engine off. The Gillig Hybrid model my city uses (RIP Phantom  ) are parallel running but the engine never turns off to power climate control and some other systems like that.
|
|
#
?
May 30, 2013 02:19
|
|
|
Are these new trolleybus systems being used mostly on BRTs and BRT lite setups? Here in Chicago, the Ashland "BRT" (no real separate right of way, just a fancy bus lane with left-hand stops) is in the planning stages, and I'd love to see it electrified. Though I doubt it would be this swank: 
|
|
#
?
May 30, 2013 02:30
|
|
|
FISHMANPET posted:A small nit to pick here, but a parallel can run without turning the engine off. The Gillig Hybrid model my city uses (RIP Phantom Gillig parallels are very, very lackluster. American vehicles in general are cheap, bid-winning buses that get the job done for 10 years but fail soon after that. The Canadian bus manufacturers (Flyer/Orion/Nova) do most of the industry R&D and build their vehicles to a higher standard, making them worth rebuilding for a 18+ year lifespan. PS: Really wish some of the older low/high floor designs were still around for circulator services. One of the agencies I've worked for in the past at the University of South Florida resorted to custom-ordering Blue Bird school buses and retrofitting them into transit buses in-house, as it's literally half the cost of buying any of the current transit models. I'll let you know how those turn out when they're done. Varance fucked around with this message at 02:57 on May 30, 2013 |
|
#
?
May 30, 2013 02:32
|
|
|
The Vancouver buses just run like any old bus on a city street. They're just 100% normal city buses that happen to get their power from an overhead line. A lot of them barely even look different from the normal diesel buses. I know some places run "trolley buses" more like a tram or LRT. They might even be big long tram-like vehicles with 3 or more segments driving down their own BRT right of way. But in Vancouver the only difference between their electric and diesel bus is the engine. Baronjutter fucked around with this message at 02:40 on May 30, 2013 |
|
#
?
May 30, 2013 02:37
|
|
|
Varance posted:That's a Gillig-specific thing, as they haven't been able to get their power efficiency down enough to allow for shutting down (Gilligs use massive Thermo King household-style A/C units, as most of their clients are in hotter areas that need them), defeating the entire purpose of being a parallel hybrid. Flyer designed their systems around the power requirements of the A/C unit and whatnot, and are energy efficient enough to allow the ICE to shut down. Orion never made a parallel. I hope we outfit our fleet with the New Flyers rather than more Gilligs, especially since the Xcelsior is made here in Minnesota. It would also make sense to go New Flyer for everything. Gillig doesn't make articulated, so those are New Flyers, and the New Flyer hybrid had a pretty amazing ride quality.
|
|
#
?
May 30, 2013 03:00
|
|
|
Going 100% Flyer makes absolute sense. Transit agencies generally stick to a single model of vehicle, unless they have multiple depots that can be tooled toward different vehicles. There's a huge cost and time savings associated with being able to stock parts for just one kind of bus. That, and your mechanics become accustomed to the vehicle layout and can diagnose/execute repairs quicker and better than having a varied fleet. Anyway, I like New Flyer. They make the best buses on the market. Driver favorite, rider favorite, mechanic favorite. The only reasons why you don't see more of them are that 1) they're more expensive than other models and 2) some agencies are required to take lowest bidder or put bullshit in the bid requirements to favor other bus manufacturers, something New Flyer doesn't put up with. Thanks, but we know how to build a bus. These are our models, this is what they cost, take them or leave them. Right now, I'm driving cutaway vans on plus (paratransit) and flex (community shuttle) routes. If my agency were to get some New Flyer C40LFR or XC40 buses as part of the CNG conversion (they won't, the entire region is dead set on Gillig), I would take a pay cut and switch over to the bus division in a heartbeat. Varance fucked around with this message at 18:09 on May 30, 2013 |
|
#
?
May 30, 2013 03:57
|
|
|
The other day I read about some European 'experiment' called a Gyrobus. A Gyrobus (pic) was a bus that used a flywheel and nothing but a flywheel for energy storage. Every bus stop had a loading station. This used high voltage to run an electric motor which in turn made a 1500 kg flywheel spin at 3000 rpm. It took between half a minute and a few minutes to get the flywheel spun up. While driving, the flywheel's kinetic energy was turned into electricity again, used to run a 2nd electric motor connected to the wheels. It could go for 6 km or so at city speeds, before it needed recharging. As you can guess, the Gyrobus had a lot of disadvantages. It was hard to go around corners because the flywheel acted as, well, a gyroscope. Usually, the stops were close enough for the bus to make it to the next one, but with heavy traffic and bumpy roads that wasn't always a certainty. And if it lost all power before the next stop, it had to be towed. Also, there were concerns about what would happen if a 1500kg flywheel with an external speed of 900km/h came loose. After a few years they decided that if they wanted the advantages of electric vehicles, simple overhead lines were a better solution. Carbon dioxide fucked around with this message at 21:06 on May 30, 2013 |
|
#
?
May 30, 2013 21:02
|
|
|
That seems like such an insane idea, I can't believe they actually built it.
|
|
#
?
May 30, 2013 21:16
|
|
|
Carbon dioxide posted:The other day I read about some European 'experiment' called a Gyrobus.  Yeah, hilariously bad idea. When you have stuff like Bombardier's Primove tech floating around now, I'm not sure why you'd want to mess with flywheels. One accident would kill your project and/or transit system ridership. Varance fucked around with this message at 21:26 on May 30, 2013 |
|
#
?
May 30, 2013 21:21
|
|
|
Baronjutter posted:That seems like such an insane idea, I can't believe they actually built it. While we're on the topic of funny stuff with gyros, let nobody forget the Gyro Monorail. Which is probably quite a bit less stupid than the gyro bus.
|
|
#
?
May 30, 2013 22:40
|
|
Yes, it's like a lava lamp.
|
That flywheel technology was even used in Formula 1: http://www.williamsf1.com/Advanced-Engineering/Media/Videos/Williams-Hybrid-Power-Flywheel---How-it-Works/ There must be something to it.
|
|
#
?
May 30, 2013 22:54
|
|
|
Well, using a flywheel to save fuel by regaining energy from braking is relatively common. It's used in some buses and high-end cars. But all those vehicles have another, primary source of energy, they aren't fully powered by the flywheel. That's why the Gyrobus is stupid, but a brake flywheel is a good idea.
|
|
#
?
May 30, 2013 23:08
|
|
|
There is also this: http://en.wikipedia.org/wiki/British_Rail_Class_139 nozz fucked around with this message at 00:09 on May 31, 2013 |
|
#
?
May 31, 2013 00:07
|
|
|
The flywheel bus was accidentally set loose when a mad scientist's lab in a castle was broken into.
|
|
#
?
May 31, 2013 00:23
|
|
|
Regular flywheels aren't a bad idea at all, but when you're putting a multi-ton spinning wheel of death on a moving object in mixed traffic, surrounded by idiot drivers and whatnot... That said, I'd expect it to work well in traditional electrified grade separated fixed guideway applications where distances are extremely short, such as airport people movers. Hell, it would even give you redundancy in case of power outage. That's the kind of vibe I get from that Class 190 vehicle linked above, though it is being used for intermediate distances and has an auxiliary diesel engine to spin up the flywheel if it slows too much. Varance fucked around with this message at 00:49 on May 31, 2013 |
|
#
?
May 31, 2013 00:30
|
|
|
Indeed, flywheels are great, especially if you don't need to make any quick turns (trains), or can be used in a non accelerating vehicle. But they do resist being rotated externally, so they're pretty bad if you need to turn quickly. Fun fact: a bunch (4?) large flywheels are used to maintain and manipulate the orientation of the ISS!
|
|
#
?
May 31, 2013 00:54
|
|
|
|
| # ? May 12, 2024 18:12 |
|
|
PittTheElder posted:Fun fact: a bunch (4?) large flywheels are used to maintain and manipulate the orientation of the ISS! Not just the ISS; reaction wheels are used for tons and tons of satellites. They're excellent for orientation control because they don't use fuel, but they can get stuck after a time. Flywheels have a higher energy density per unit weight than batteries, which makes them great for applications where weight is important (e.g. Formula 1 races, aerospace). A smart designer will use both of their advantages together: they resist changes in orientation, and they store a large amount of energy with very few losses. Using them for steadicam batteries would be a great example. Anyway, in unrelated (but indubitably good) news, I'm now officially a PE. I was in the midst of a pretty nasty fever today at work, so I almost didn't believe it at first, but it's starting to sink in now.
|
|
#
?
May 31, 2013 01:27
|
|