The motors used are induction or asynchronous motors designed to have characteristics suitable for traction. The speed and torque of the motor are controlled by varying the frequency, voltage and current applied to the stator coils.
The fundamental difference between trams and trolleybuses is that trams have flanged wheels and run on rails like a train [whether on reserved track like most railways or in streets on grooved track installed flush with the road surface]; whereas trolleybuses have conventional rubber tyres for ordinary road surface and …. In many of these places, trolleybuses are the backbone of the public transport system.
The trolley — a passenger vehicle powered by overhead wires, electric rail system or by horse. Skip to content Miscellaneous. Reverse thrusters are used to slow down airplanes. Is that better than a normal engine retarder and service brake?
It also minimizes wear on friction-based braking elements, allowing the service brakes to last longer. We hope you loved this article. If so, please consider subscribing or donating.
The Urbanist is a c 4 nonprofit that depends on donations from readers like you. He has shown in over forty photography shows is also the director of nine films, six of which have shown at festivals, and one of which premiered at Henry Art Gallery. As an addition, I understand that some newer trolley buses available on the market have big batteries and can run for five miles off-wire. Also there is a new kind of battery-powered electric bus in Switzerland that runs without wires and recharges itself via occasional rapid charging with a quick connect-disconnect device that operates for 15 seconds at selected bus stops.
In Utah there is a wireless electric bus that recharges its batteries inductively with a no-contact electric pad used for a period of minutes while the coach is parked above it between runs. There is wear and tear from ongoing physical contact with the wires. They operated electric in the tunnel via the trolley wire, and then switched to diesel once they left.
They were notorious for being unreliable, something that has persisted since the diesel engines were removed and the busses made electric-only. The extra equipment made them extremely heavy as well. Trolley busses can also have an Auxiliary Power Unit to allow them to move if they throw their poles or loose power.
Most busses use batteries now including the new fleet Metro is procuring , but I know the trolleys in Dayton use diesel APUs — basically making them an early series hybrid of sorts. For a period of about 15 years after the opening of the Seattle downtown bus tunnel, King County Metro Transit operated a fleet of Breda buses that switched between electric trolley operation in the tunnel and diesel operation on the streets of the region. They were removed from service when the tunnel was closed in by Sound Transit contractors to convert to joint operations with light rail and buses, which began in The tunnel catenary was configured for light rail, and upon reopening the tunnel in , only non-catenary buses were allowed in it.
The technology used for the buses in this tunnel now is diesel-electric hybrid. There is a short dead zone between the isolators if the trolly takes the upper leg B. The part 4 is just a bus bar and termination - nothing moves. But if there's no switch in the catenary, how does the trolley pole pass the switch and to go the correct direction? Add a comment. Active Oldest Votes. Improve this answer. Bruce Adie Bruce Adie 11 1 1 bronze badge. I'm sure that many ingenious solutions have been invented to manage the switching but here's one: The switches of the trolleybus network are controlled by the driver of the trolleybus.
Transistor Transistor 6, 2 2 gold badges 14 14 silver badges 25 25 bronze badges. Also you don't explain how the mechanical switch 2 and 4 works. Also this fails explain how it'd work for retro tramways using only a single trolley pole. As for single trolleys, I never did find out how those worked, though I always figured it was just mechanical pressure on the switch. Also, I'm sure Transistor's answer is applicable to many trolley systems.
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Does ES6 make JavaScript frameworks obsolete? Featured on Meta. They were comfortable, quick and quiet, and they seemed to be fitted with particularly comfortable suspension. We would often let a couple of double-decker buses pass if we knew that a trolleybus would soon be along.
From the perspective of today, trolleybuses were years ahead of their time: They were 'clean and green' because the ran on electricity. They even had their own batteries which could power them up to around four miles to different parts of the network or to the depot if their booms became damaged.
It is surprising that these advantages seem to have been treated as of little consequence at the time, particularly in view of the serious pollution due to coal fires in the home and for industrial use.
The advantages of trolleybuses that the people of the time valued is described in the coloured box. Although 'clean and green' methods of moving people around is very important today, the London trolleybuses didn't last for much more than the first half of the 20th century. In London Transport decided to abandon the trolleybus system, citing its lack of freedom to move from one side of the road to another, around accidents or road works.
I well remember with great sadness not long before my 5th birthday, that most of the routes in Plaistow where I lived had closed. Waiting at the bus stop with my mother and looking up at the site of the wires cut down or tied together around the lampposts had a strange effect on me.
A few routes were left running for another 2 months or so, but the inevitable end of the trolleybus in the east end of London was a time of sadness for one so young. From humble beginnings in the south west of the capital to the very last trolleybus that entered Fullwell near Twickenham depot in the early hours of 9th May, the London trolleybus system had been the largest in the world, and for those of us who travelled on it, even as fascinated youngsters, was something that has become indelible in our lives.
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