Cat m wreck

[66ken]

Since this is simply a speculation, not pointing fingers, simply making a comment.

When I look at the first picture I do not see any sign of striking the ground at speed. No skid marks down the bank behind the machine, no sign of the left end of the blade gouging into the ground, no scuff marks on the sides of the tires/wheels as if they skidded on the ground.

Hmmmmmm. Would it be possible for this machine to start this crash at 14mph and lose all that forward speed before it struck the bottom of the ditch?? Hmmmm.

Maybe some of the techno guys can answer this. Is it possible to retrieve data from the computer indicating the gear and speed of travel just prior to the crash?? If so would it also be possible to retrieve each of the requests the computer received just prior to crash?? :beatsme

Yes it is possible to retrieve the data. Some is already known, and the rest is still being looked at. Not sure when we will know everything.

 

[AtlasRob]

For the rest of us... that would be about 18.6 MPH...

30kph sounds a lot faster though

Still kicking, just thanks for asking.

 

[sdPete]

Since this seems to be a lottery to guess what happened and just like Butts, everyone's got an opinion, I'll offer mine.

I don't think he was pushing snow because there's none on the bridge deck. Also no leftover windrow of dirt/gravel.

Look at the powdered snow buildup on the back side of the blade. That usually develops doing snow at high rate of speed. Does not necessarily mean he was moving at high rate of speed when he approached the bridge, but guessing low speed fails to explain other things.

I don't think he was going fast at all. Maybe walking speed or a little above at best. I base that on the minimal damage to the machine, didn't even break off the front lights. I credit the cab being leaned back to the shape of the ditch it fell in and the idea that it went off the bridge rear tires first. If he had erroneously steered hard left it would have taken more of a nose dive. The bolts that were holding the railing on aren't bent over toward the forward end of the machine like they would be with forward momentum.

Look at the blade scrape on the edge of the bridge deck as well as how and where that scrape ends relative to the location of the machine. Now think about how that could occur had the rear wheels gone off the deck first.

The bridge railing appears to be wooden. By going off rear first the blade pushed the railing ahead of the machine and didn't even break a lot of the rail boards.

I think he drove the front tires onto the bridge with his left tire just missing the bridge marker sign at the approach with the grader tracking straight. Doing so to clear the right side railing with the blade. The front rear tandem tire would go onto the bridge about the same time as the right end of the blade. At the last second he thought he was going to hit the right railing and spontaneously twisted the rear steer to clear the marker. Or could have possibly mistakenly twisted the wrong joystick in an attempt to rotate the table.

When I drive the 140M here at snow plowing speeds, rear steer/articulation is not even a considered option for maintaining control. The only left hand movement my brain will consider is left/right movement of the stick for steering, it is very difficult to even raise/lower the left end of the blade slightly while steering, I have to be on a stretch where the machine can run straight as long as it takes to tweak the left end of the blade to make that happen. Maybe that is just me. Fine tuning the blade for me is best done by using the right thumb switch to roll/curl the blade up and down. If I were to find myself in a high speed emergency situation where articulation was attempted I doubt if the outcome would be good, to which you might say AHA see he went off the bridge, but then you have to explain that long blade scrape on the deck.

With a very weak railing design the bridge did nothing to deter the machine from driving off the concrete deck. Once the rear tires started off the edge there would be little that could be done to retrieve it. With his blade low to the ground it became a steel runner and contributed further to the rear of the machine taking a hard left turn.

Review the bridge deck edge blade scrape discussion earlier in the response

Someone commented about other operators having ran off the road. One time I was pushing snow and running about 14 mph. I came to a hard right turn on a narrow gravel road that was frozen solid. I had my moldboard turned to roll snow to the right. When I approached the curve and started my turn the front wheels started slipping. The locker was on. The machine only made a slight attempt to turn. Within a second I was doing a front wheels cramped, 14 mph slide, headed for the bank off the outside of the curve. A lot of things go thru your mind in that second and most of them are wrong. All I could make myself do was jam the blade into the roadbed, thinking it would stop me. What it actually did was lift the weight off the tires and I found myself skidding on a 14ft steel runner. I went off the road and down the bank stopping in a flat bean field. After I cleaned the seat I turned off the locker, lifted the blade and drove back up onto the roadbed. I was a lot more cautious the rest of that night.

Noteworthy that you did not mention the thought of articulating/rear steering, not that I think it would have helped, just observing your recollection. I have scraped ice with enough down pressure to negate steering, never went in the ditch but did learn to keep my hand on the left blade lever at all times.

 

[ovrszd]

SDPete, I still can't see that the machine left the bridge with 14 mph forward speed. The scrape you are talking about actually would indicate that the machine had lost all forward motion before it left the deck. The powdery snow on the moldboard only indicates to me that there was a dusting of snow on the roadbed. I've done gravel maintenance to a frozen roadbed with a dusting of snow and got the same effect on the moldboard. Sure is interesting to speculate though huh.

 

[sdPete]

scrape and speed

You are right in thinking the speed of the machine at the point it fell off the bridge was either slow or zero. But I am guessing there had to be quite a bit of speed as the machine approached the bridge, otherwise I have a hard time explaining that scrape. If the left front wheel pushed through the rail and went off the bridge deck, I could believe the blade then cut its way along the edge of the deck until forward speed was used up and/or the left rear wheels went off the deck. Likely the grader would tip when the left rear wheels went off the deck, lot of weight back there and the center of balance would shift past the tipping point. Not a pleasant situation for the driver.

 

[Grader4me]

Hey there sdPete, your forcing me to put my specs on to read your posts. Be interesting when the story comes out as to what exactly happened.

 

[LowBoy]

I'm with Grader4me...she'll buff out.

"Bondo & Paint'll make 'er what she ain't..."

Glad to hear the pilot was O.K., besides being poster boy of the month for Fruit 'o The Looms undergarment company.

 

[Grader4me]

I'm with Grader4me...she'll buff out.

"Bondo & Paint'll make 'er what she ain't..."

Glad to hear the pilot was O.K., besides being poster boy of the month for Fruit 'o The Looms undergarment company.

Good lord, the dead has arisen! Good to see you back! Figured you must have went on your final run..

 

[Tracksoup71]

Another possability is that the blade hand had punched the left front tire through or over the guard rail at a higher rate of speed and came to a stop upon doing so. Being stuck on the guard rail and not wanting to call anyone to save face, desided to try to get himself out on his own. After a little jocking around, the older style wooden railing may have given way under the weight, twist, and torque, pulling the machine off over the edge. This would explain the zero to no speed when going over, the scrapes on the bridge deck, and the fact that the railing seemed to have come off in one big chunk instead of pieces like you would expect if the grader had blown through the rail. Just another theory of coarse, but a plausible one. Working at a big gold mine, myself, I see a lot of people in the seats of equipment who are lacking the "molecular structure" to become any kind of on operator or already know everything and can't be taught. (Unfortunately, in a big company like that, they're not too concerned about wether they can truly operate, as much as their concerns for filling the seats for their quota to look good for corporate!! AAAARRRRGG!!!) Anyways, we had a blade hand actually rip the moldboard of the circle frame trying to get himself unstuck just so he wouldn't have to buy doughnuts for the crew. (That was the unspoken company rule at the time.LOL) That was 5 or 6 years ago...you are going to laugh at this.....He was never fired, infact, today he is the designated grader trainer for that crew( not mine thank God!!) and he still doesn't run blade worth a hill of beans. Now don't that beat all!!! It will be interaesting to hear the actual story on that grader going over the bridge, that is if (depending on the company) they release the actual story and not just what sounds good in the "public eye".

 

[AtlasRob]

Another possability is that the blade hand had punched the left front tire through or over the guard rail at a higher rate of speed and came to a stop upon doing so. .............................................. It will be interaesting to hear the actual story on that grader going over the bridge, that is if (depending on the company) they release the actual story and not just what sounds good in the "public eye".

A very good thought, the only question I would raise is would you still expect the cab to be layed back if she only ( only, ha ha) rolled off the side.

I aint arguin!....... just askin .

 

[Tracksoup71]

Hey AtlasRob,

The way figure it, if the right wheels caught on the bridge deck as she went over, flipping the grader completely up side down before letting go, it would have landed cab first, especially if the front wheel hung up a little longer than the rest. If the cab hit first on a little bit of the incline of the creek bank on that side, I would think it would have given it enough forward momentum to do exactly that before the rest of the machine hit the ground, and then roll on it's side half under the bridge where it rests in the pictures. In my proposed theory, this would be the only way I could see the cab being rolled back like that. But as I said before, it's just a theory. It's always fun being an arm chair investigator, so if you are wrong, there's no harm done. But if you're right, you've got the bragging rights to say, "I told you so!!" LOL.

 

[AtlasRob]

But as I said before, it's just a theory. It's always fun being an arm chair investigator, so if you are wrong, there's no harm done. But if you're right, you've got the bragging rights to say, "I told you so!!" LOL.

:salute sounds pretty convincing to me :yup

Just glad nobody was seriously hurt and just as important.................it aint mine

 

[bugeater]

Maybe this has already been posted.

The Assistant County Engineer has commented that this accident was operator error. They are not 100% sure what happened, but they believe the operator was going to fast for the conditions, and lost control before he came to the bridge.

The unit was totaled and the county ordered another Cat 140M.

 

[JDOFMEMI]

I wonder what the operator had to say about that?

 

[I AM IRONMAN]

Maybe this has already been posted.

The Assistant County Engineer has commented that this accident was operator error. They are not 100% sure what happened, but they believe the operator was going to fast for the conditions, and lost control before he came to the bridge.

The unit was totaled and the county ordered another Cat 140M.

Bugeater- I wonder why they have kept this so hush hush?
You would think that there would be some Public information about it, but I can't find anything in any news articles or any Public meeting minutes, etc.
It seems like that there is some kind of cover-up to me.

Can you tell us any more???:beatsme

 

[Jt13speed]

Ever since these newer graders came out, i have wanted to run one so bad. I got to sit in one at an equipment show, and just the feel of the joysticks was great, and the thought of not having to look at all those levers in front of me was awesome. But now seeing this its kinda un-nerving! Hopefully someone figures out what really happend.

 

[Old Grader Guy]

Reversing with M-Series Grader

One of the complaints related to the joysticks is driving in reverse. Think about it: You cannot turn your body as your hands are on the joysticks. So, you must twist your neck, ouch!
With the steering wheel, you keep one hand on it and you turn to side without problem (like reversing with the car).

 

[keerym]

You can take your hand off of the right joystick when you back up. Its actually a lot less dramatic than some people make it out to be. Your not flying an F-16.

Seriously though, most people are uncomfortable in an M because they think they need a death grip on both joysticks. Operators do much better when they relax their grip, get the controls adjusted properly, and stay calm.

Adjust the sticks so your elbows are ahead of your shoulders, and your wrists are below your elbows. Also, adjust the side consoles so you have some support under your forearm. Also remember if you slide the seat forward, you need to readjust the controls to match. This will help a lot.

 

[Old Grader Guy]

Another issue is that the graders are often bouncing, especially at higher (transport) speeds. With your hands on the joysticks you do not have any support. Actually, it is easy to accidentally move the joystick in such situation.
Don't misunderstand me: I like joysticks for blade control but I for sure believe that steering with the joystick is hazardous.

 

[keerym]

Another thing people don't realize is there is a switch in the cab that kills all hydraulics except steering for transport. The steering is also speed sensitive to ensure that the front tires can't be steered too fast during transport.

The joysticks are also mounted to the floor of the cab, not the seat. I'm told they did this to minimize the amount of joystick input over rough terrain. If they were mounted to the seat you would constantly be bumping the controls. I've seen guys hold the bottom of the joystick in rough terrain because its a ridged mount to the cab. They can hold on while the seat bounces.