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Oops!

pd
Grafter
Posts: 235
Registered: 09-05-2008

Oops!

20 REPLIES
matt_2k34
Grafter
Posts: 1,300
Registered: 09-07-2007

Re: Oops!

Ahaha
Thats quality someone had a vengence Tongue
Community Veteran
Posts: 3,291
Thanks: 2
Registered: 10-08-2007

Re: Oops!

Old Stuff
This video was posted on liveleak on Sept 11. http://www.liveleak.com/view?i=347_1252677023
The BBC are as bad as ITV for dragging up stuff from the net and making news items from them weeks after the actual event
Community Veteran
Posts: 7,153
Thanks: 54
Fixes: 2
Registered: 30-08-2007

Re: Oops!

Yes, the Beeb aired it as a questionable parking issue, rather than a serious accident.
However, as a bus/coach driver, there is some intense discussion going on as to how this happened (as you might imagine) among us. Apparently the driver is unavailable for comment (assuming he still works for the company, which from my experience he probably doesn't) an initial comment was that he put his foot on the accelerator rather than the brake...have you ever seen the pedals in a bus, most are nothing like a car, usually full foot sized plates, and very difficult to mix up. Buses simply don't normally accelerate that fast over that distance, and would be quite easy to stop "if" the driver "had" pressed the wrong pedal.
On the assumption it is not some obscure suicidal move by the driver, "we" suspect a mechanical problem; over-speeding (runaway) diesel engines are very rare, but not entirely unknown. We will be watching out for the investigation results with great interest.
Experience; is something you gain, just after you needed it most.

When faced with two choices, simply toss a coin. It works not because it settles the question for you. But because in that brief moment while the coin is in the air. You suddenly know what you are hoping for.
Community Veteran
Posts: 6,111
Thanks: 1
Registered: 05-04-2007

Re: Oops!

Quote from: Petlew
and would be quite easy to stop "if" the driver "had" pressed the wrong pedal.

Indeed, I know buses have very sharp brakes as a safety feature... even on London's roads (which aren't generally conducive to high speeds) you can really feel the effect sometimes.
john
Newbie
Posts: 7
Registered: 30-07-2007

Re: Oops!

They have a retarder fitted to supplement the air powered friction-based braking system.
VileReynard
Seasoned Pro
Posts: 10,588
Thanks: 193
Fixes: 9
Registered: 01-09-2007

Re: Oops!

What's a retarder?
(Apart from something to slow you down). Grin

Community Veteran
Posts: 7,153
Thanks: 54
Fixes: 2
Registered: 30-08-2007

Re: Oops!

For a somewhat complex answer to "diesel retarders" see: http://en.wikipedia.org/wiki/Retarder_%28mechanical_engineering%29
Most buses over here are fitted with the electronic type, in the U.S some types can be very noisy in operation leading to local bye-laws that require them to be switched off in residential areas. Some drivers over here (a very small number) prefer to drive with the retarder switched off. In operation while they work in a completely different way, they can be compared with a brake servo, but not ABS, it will not stop a bus skidding.
Experience; is something you gain, just after you needed it most.

When faced with two choices, simply toss a coin. It works not because it settles the question for you. But because in that brief moment while the coin is in the air. You suddenly know what you are hoping for.
Community Veteran
Posts: 7,153
Thanks: 54
Fixes: 2
Registered: 30-08-2007

Re: Oops!

Loidis is indeed quite right about air brakes. If you've never used them, one peculiarity about air brakes is that, if you sit for a long time with your foot on the brakes, it is possible to empty the air tank that controls them. The compressor should keep the air tank topped up irrespective but, anomalies do happen. Should the air tank reach a low level the brakes will be applied until such times that the compressor replenishes the tank.
You will occasionally hear on traffic broadcasts that a truck or coach/bus is stuck with its brakes locked on. What has usually happened is that there is a failure of the air compressor system of some sort. This can be due to poor maintenance. Unfortunately in the case of a bus/coach it will either need to be towed by a heavy recovery vehicle which has auxiliary air supply, or uploaded on to a very large low loader, since the vehicle needs to be over a pit to get at the offending area.
Usually, before an air tank empties a series of alarms will sound in the cab. 
Experience; is something you gain, just after you needed it most.

When faced with two choices, simply toss a coin. It works not because it settles the question for you. But because in that brief moment while the coin is in the air. You suddenly know what you are hoping for.
Community Veteran
Posts: 16,848
Thanks: 1,135
Fixes: 13
Registered: 06-11-2007

Re: Oops!

From the footage, it looks as though the bus driver was in a hurry to get back on schedule, but he was parked (stopped) extremely close to the bus in front of him, and he must have known he was going to go all the way across the other side of the road, to be able to get away from the stop , from that position, hence his "hard right" approach to the steering wheel... His "pulling away" speed, certainly seems to be more akin to the start of a grand prix race circuit, which would account for his inability to recover from his "hard right" ...
Community Veteran
Posts: 7,153
Thanks: 54
Fixes: 2
Registered: 30-08-2007

Re: Oops!

Well anything is possible Gerry. I've just sat here and viewed the accident section of the video nearly 20 times. The bus in question has reached a "quite high speed" within the length of the other parked bus maybe 35-40 feet, how close together they really are before any movement can be very deceptive, there was obviously enough room to make the turn out, unless out of sight (while the other bus was passing) the driver reversed to make room.
At the expense of appearing defensive to an unknown "colleague" the problem maybe related to the car that was stopped, as its brake lights went off and the car very briefly moved forward and "lurched" to a stop (the front went down and the rear rose up, albeit not much) This may have caused the accident bus driver to take evasive action to avoid a head-on with the car. Quite obviously, neither the car driver nor the bus driver due to the passing bus knew the other was there until the passing bus was clear.
The owner of the Porsche has a lot to answer for, for not only parking on a bus stop but causing an obstruction that reduced the available width of the road.
Most bus drivers I've encountered and worked with are not too concerned about minor running time stoppages, there are usually plenty of points to easily catch up in a route timetable.
Experience; is something you gain, just after you needed it most.

When faced with two choices, simply toss a coin. It works not because it settles the question for you. But because in that brief moment while the coin is in the air. You suddenly know what you are hoping for.
pierre_pierre
Grafter
Posts: 19,757
Registered: 30-07-2007

Re: Oops!

More on Brakes.
The original  retarder was a Telmar, this is an Eddy  Current brake, a large rotating ring was on the drive shaft just before the drive axle, this was supplied with a large current to four different coils.  There were several different sizes to match the vehicle and were capable of retaarding it down a long Alpine pass.
Then there were Exhaust retarders, these shut off the flow of exhaust gasses and hence the engine was in effect a large compressor.
On to air brakes.  Most applied the brakes by a large spring, the air held them off , thus to apply the brakes, the pedal bled off the air.  No air in system or a leak, the brakes came fully on
Normal small vehicle hydraulic brakes do the opposite, you fed a higher pressure of fluid to the wheel cylinders which then applied the barkes, get a leak or in the case of cooking them with old fluid, the water in the fluid boile, created a space which stopped the brakes being applied.  Net result, no fluid, no braking
john
Newbie
Posts: 7
Registered: 30-07-2007

Re: Oops!

Quote from: Crucibleofevil
What's a retarder?
(Apart from something to slow you down). Grin

This video on youtube will explain

I work for Optare which makes these http://s261370817.websitehome.co.uk/gd/scaleImage2.php?image=32631Solo_EV_at_10_Downing_Street.jpg&m... (The one pictured is a electric) which use a KLAM electro-magnetic retarder which is automatically activated when the brake pedal is applied.
pierre_pierre
Grafter
Posts: 19,757
Registered: 30-07-2007

Re: Oops!

pull up a bucket and I will tell you about one of my Builds.
The photo shows A Ford Cargo with experimental Air Cooled Mag-Duetz V engine, the two in brown are Mag-Duets engineers, at the back of the artic is my concoction.  An ex tipper chassis with twin rear axle and  two of the Largest Telmars available., in the back of the tippers Concrete ballast to provide traction, a 2 litre Diesel engine and alternators to feed a set of batteries to power the Telmas,  then a twenty stage controller for the braking.  at max loading it would hold back the biggy engine at the front  in first gear.  I think from memory (it  was about 1980) about 400 HP.
Last time I saw the dyno trailer it was at Millbrook Proving Ground
Community Veteran
Posts: 2,924
Thanks: 169
Fixes: 3
Registered: 05-04-2007

Re: Oops!

While I know nothing about buses (unlike some of you Smiley ), the BBC claimed the car was written off.
From the footage, it had a bit of a shunt from behind. How did make a 30k car a 'write off'?
I feel the BBC are getting as bad as ITV (hard to believe anyone could be worse than them, I know).
On a more serious note, it was fortunate no-one was under the bus shelter Shocked