Bendy buses

Okay as a avid petrol head and engineer i have finally broke and have to ask

bendy buses how do they work ?

For those that have not seem them they are a bus with a flexable bit in the middle meaning they can be longer and more maneuverable. Now here is my question the engine appears to be in the back bit of the bus as in after the flexable bit and the steering is in the front half which has two axles but the back half with the engine in it has only one axle. now i would of thought that this would of caused all sort of strange behavour with the "trailer" part of the bus pushing.

Or is there some strange method of transmitting power to the front bit from the trailer.

I don't know if the powered wheels are in the rear, but I have heard of jack-knifing (the guided busway in Nancy, France was shut down because of this if I'm remembering correctly) so it's possible.

The technical name is "articulated".

Hmm. I don't know this for sure, but I'd suspect a prop-shaft with a universal joint (or 2). It's not like those buses bend 90 degrees.

Some of the bendy buses I have observed here in Canda have the motor in the "front half". They operate as if the rear half is just a trailer being towed by the front half. Simple.

Cheers

http://www.nabiusa.com/resource_page.cfm?res_id=11

Some of the bendy buses I have observed here in Canda have the motor in the "front half"

Same here in Sweden - looks like the engine is mounted "lying down" so not to steal as much height...

But looking at Volvos site there appears to be at least one with only engine at the rear. It also looks to be no, nor room for a, shaft going the forward part. Interior floor is only 30-something centimeters above the ground, but only 23 centimeters when stopped and "courtsying" (sp?) to simplify for people getting on/off. Then the link/pivot is probably about 10-15cm thick...

Hmmm, could they be using some sort of locking/damping mechanism in the pivot to stabilize things?

/Michael

The bendy buses here are rear wheel drive, in the front section, not the rear. The rear segment is unpowered.

The joint is a pretty clever constant radius thing, a bit like the Jump-wipe mechanism on Mercedes saloons.

Heres a photo of a NYC articulated bus with the/an engine quite definitely in the back, and only one axle on the rear section.
I remember seeing these growing up in NYC, and I always wondered how they work.
Still dont know...

Ah ha!!

Link

There are pusher and puller type bendy buses. The first paragraph kind-a explains it.

Franky I think the Seattle dual modes are more interesting.

We have those in Boston too.
Well, in Cambridge, Watertown and Belmont anyway.

Theyre kind-a cool, except the overhead cables are a bit of an eysore. And the buses are a bit on the aged side.
Rumour is Boston will be going CNG soon.

We dont have any bendy buses, but we do have swan boats.
And the worlds smallest suspension bridge.
whee...

And the worlds smallest suspension bridge

Which is apparently also the World's widest suspension bridge too. They should have called it The Stubby Bridge or something.

You've asked a question that has puzzled me for sometime, the Leeds one's have the engine in the rear section.

In Amsterdam, they have them in three sections( No I had not been on the loopy juice and it wasn't a tram!), heaven knows how they go in reverse. I wish I had had my camera

Well, if they power the middle section at least the problem is symmetrical.

pca

Could it be possible that the engine is used to generate electricity to power a motor that drives the wheels, at least in the front section? It takes much less space to house large wires and cables than shafts and universal joints.

No, it really is mounted behind the rear wheels, for easy access, in the trailer part of the bus, normally geared to the "C" axle - seems illogical, you don't usually put the engine at the back of the train - unless your a Dutch railway engineer, or the train operator from London to Cambridge, cutting corners, but it's a fact.

We have those in Boston too.

They're not dual mode.

Seattle has buses that run tot he end of the wire in the tunnels, drop their poles, and drive away.

drop their poles, and drive away

So what races can stay after the poles go, Czecks, Serbo-Croats, that sort of thing?

I wasn't paying attention. Luckily no one noticed I'm 1/4 Polish.

So what races can stay after the poles go, Czecks, Serbo-Croats, that sort of thing?

Anglo-Irish

I guess what I'm saying is that maybe the engine drives the rear wheels and also transmits power for an electric motor to the front part. I don't even know if that really makes sense; it's just a notion.

here is a page with some short blips about the SF Muni trolley busses. They are called "articulated" busses. The new ones are designed by Hubner.

If you guys really want to know the details, just call Mike Hursch (sp?), 415-401-3118, the Chief Engineer of MUNI. I called around Muni a few months back because... well, here's why. He's a really nice guy and can tell ya what you wanna know or direct you to someone who can. Sometimes the web can't answer everything. =]

They are called "articulated" busses.

They were also called that about 10 messages ago when I said that

As to why, actually, well, the web could have answered that, if you'd looked in the right places.

One of the problems with collecting power from overhead wires is ice buildup as well as things which cause the wheel or shoe to bounce slightly away from the wire can cause arcing. Sometimes it's more serious than others, and sometimes it just goes on in one place frequently, and the wire burns through and comes down.

A pole can also come off the wire, spring upward and tear down the support wires, bringing the whole thing down. There are other failures.

The wire can stay live after it comes down, depending where the substation is and if it was grounded and tripped the breaker in the substation.

Interestingly a car with heavy current demand can also trip the breaker if you try to accelerate too fast. Our local trolley museum has a smallish sub that can occasionally be tripped by some of the balkier cars when a motorman with a heavy hand or foot is at the controls.

And there are also on-vehicle breakers. At least once as a random rider on one of the older Pittsburgh PCC streetcars which are now retired, the motorman went to pull away and tripped the breaker. He got out, reset it, and tried again. The car moved, and the breaker tripped again.

We were a few hundred yards from the maintenance facility, so they sent down another old car with a towbar to tow that car back to the "barn", and then a few minutes later a car went the other way to a loop up the line a bit, turned, came back, and picked me up for the remainder of the relatively short ride I was taking as a joyride.

They're not dual mode.
Seattle has buses that run tot he end of the wire in the tunnels, drop their poles, and drive away.

http://www.allaboutsilverline.com/

"Traveling on city streets, Silver Line vehicles burns low-emission fuel, and underground they will convert to electricity, a zero-emission energy source."

This is the latest and greatest in Boston BRT. (Bus Rapid Transit)

Did they actually get the buses? The last update I had was they had straight CNG buses running, and nothing that used wires, on the Silver Lie.

And that site agrees that they're not the final buses to be used, either:
http://www.allaboutsilverline.com/news.asp

"Initially, 40-foot buses will serve the Washington Street
Corridor, but they will be replaced in less than a year by
new 60-foot, articulated vehicles. "

They keep extending the completion date. And changing the facts around. I remember when this was all first rumoured about 6 years ago. Boston city planners... move.... very..... slowly.....

"Silver Lie" is very apt. I like that.

"Silver Lie" is very apt. I like that.

Stolen from somewhere. Wish I remembered where.