How did this tanker topple on a flat 10 km/hr road?

[Ram]

Dear friends:

I’ve been travelling by road between Mumbai and Pune for the past forty years or so.

Even as a kid, I’d always wondered how big trucks could manage to “lose their footing” and land on their sides, like resting elephants.

Later on after reading about centrifugal forces acting on a truck cornering at speed, one could imagine a severe impetus to overturn.
A truck driver, could also misjudge the angle of a sideways slope sharp enough to throw the truck’s centre of gravity outside its track, causing it to keel over.


But this morning, I saw a tanker lying on its left side, completely blocking the expressway turnoff to a petrol pump and restaurant area.

Location: the turnoff for the HP petrol pump at Khalapur-Sajgaon on the Mumbai-Pune expressway, just a few hundred metres after the Khalapur-Sajgaon toll station. This is the first toll station on the Mumbai to Pune expressway.

A perfectly flat good concrete surface at a spot where vehicles slow down to 10 km/h to enter the rest area.

It was carrying highly flammable nitrocellulose thinner, which was pouring out of its four filler necks, onto the road. Had it been a tar road instead of a concrete one, the NC thinner would certainly have dissolved the tar and caused it to run into the gutters.

A Khopoli local municipal fire truck was on the scene and rescue personnel stood about wearing scarves around their noses, totally at a loss as to what to do.

Here’re pics.







Does anyone know any more about this?

[hrag]

The Metrowater lorries in Madras used to be famous for toppling over until someone realised that the tanks didn't have internal compartments.

In the absence of these internal compartments, any slight movement by the tanker to the left or right caused the entire mass of liquid in the tank to move around, causing instability.

Could this case be similar?

[tsk1979]

As for the 10kmph speed its entirely possible that the tanker was doing 40, saw the zone, braked a little too hard, and the banking on the road worked as a catalyst.
Also I have once seen a truck go into launch mode. It was overloaded, and when the guy started the truck, engaged the first gear, the front wheels lifted and it was ready to be launced into orbit.

[Zappo]

Originally Posted by tsk1979

Also I have once seen a truck go into launch mode. It was overloaded, and when the guy started the truck, engaged the first gear, the front wheels lifted and it was ready to be launced into orbit.

A truck?!! Doing a wheelie?! Huh... I would have loved to see this

[Joz]

Originally Posted by Zappo

A truck?!! Doing a wheelie?! Huh... I would have loved to see this

On Sunday I saw a tractor doing a wheelie on the Bangalore Mysore Expressway. Beat that!!

The tractor trailer was overloaded with sugarcane and as it tried to go over a steep speed breaker, the front would lift off. The driver stops eases off - two workers sitting on either side of the driver, promptly got of their vehicle and perched themselves on eaither side of the front bumper. With the additional weight in place, the it crossed the speed breaker with minimum lift.

I was amazed, amused and horrified, all at the same time. So much for an expressway.

[DRC]

I too have seen a tractor doing the wheelie, but never seen a truck though..

About the trucks toppling, there are many stories behind them.. some facts and somme fiction..

[tsk1979]

Originally Posted by Joz

On Sunday I saw a tractor doing a wheelie on the Bangalore Mysore Expressway. Beat that

Bangalore mysore expressway? Thats an oxymoron, right?

[v1p3r]

Originally Posted by Joz

On Sunday I saw a tractor doing a wheelie on the Bangalore Mysore Expressway. Beat that!!

I have driven a tractor and popped a wheelie. Beaten!!!

[Joz]

Originally Posted by tsk1979

Bangalore mysore expressway? Thats an oxymoron, right?

I agree. With the existing stretch it will never be. It currenlty does a great job of being a sure shot receipe for disaster!! There was truck which was toppled at one of the points where the road becomes 4 lane to 2 lane with no warning. The guy apparently was coming at average speeds in the night and realsied to late that there was a diversion ahead. Trying to turn right and then left with all the momentum, it toppled. The driver escaped with minor injuries.

That brings us back to the topic. Momentum - i think thats what topples these trucks.

V1p3r: I have driven a tractor too, but couldn't manage a wheelie. Looks like i need to learn a few things from you.

[v1p3r]

Originally Posted by Joz

V1p3r: I have driven a tractor too, but couldn't manage a wheelie. Looks like i need to learn a few things from you.

Track day, here we come!!!

[Rudra Sen]

Moderator's note: Guys, please do not go outside the topic please.

[Ram]

Originally Posted by tsk1979

As for the 10kmph speed its entirely possible that the tanker was doing 40, saw the zone, braked a little too hard, and the banking on the road worked as a catalyst.
Also I have once seen a truck go into launch mode. It was overloaded, and when the guy started the truck, engaged the first gear, the front wheels lifted and it was ready to be launced into orbit.

As you can see from the original pix, the road was not banked at all.

After one has stopped to pay the toll at the Khalapur tollstation and started rolling, one reaches the petrol pump/restaurant turnoff within 100 metres. There's not enough distance for a heavy truck to build up the kind of momentum needed to overturn.


HP pump on Mumbai-Pune expwy at Sajgaon,Raigad refuels Neeta Volvo coach. Foodtrack, the travelers!

[Rehaan]

Originally Posted by ram

After one has stopped to pay the toll at the Khalapur tollstation and started rolling, one reaches the petrol pump/restaurant turnoff within 100 metres. There's not enough distance for a heavy truck to build up the kind of momentum needed to overturn.

I think a 100meters is enough distance to get the truck up to a speed at which it can overturn on a sharp steering input.

any slight movement by the tanker to the left or right caused the entire mass of liquid in the tank to move around, causing instability.

I agree with hrag here, this is a reason you should never overtake tankers on or just after turns...

cya
R

[DRC]

The dynamics of a tanker are largely different from that of a truck..

My friend had shown me once, Just accelerate hard (imagine a truck) to just about 10KM/h, and brake, with half load in the tanks, the thing jumps like a frog and shows no signs of stopping..some times it jumps backward too It just depends on which direction the force is applied,

[tsk1979]

Me too!, since the plough was down and ground rocky and uneven the plough got stuck. The tyres were spinning and tractor started sinking in. We disconnected the plugh and tried to go forward and the front would come up. So we have to put planks, make two guys stand on the front and then it came out. If it hadnt next step would have been to tow it using the gypsy!