I'm researching scrapers and tractor-scrapers right now from the perspective of mass grading and excavation. I have a few questions and if anyone can lend advice or their 2 cents, I'd be very grateful. Here are some questions I have: 1. What are the advantages of having a tractor and a pulled scraper/pan setup vs a wheel-tractor scraper machine? Are there certain jobs or conditions where one beats the other? 2. What are some ways you can boost scraper production after rain/soft/wet soil conditions? Is push-loading the best way to do this? 3. Do companies prefer buying new or used pans/wheel-tractor scrapers, in the sense like an excavator, or are they more hesitant of used machines because of the wear and tear? 4. How much extra fuel burn do poor haul roads cause? I took a look at the CAT performance handbook and estimated it to be 15-25%, does this match what you see in the field? 5. How do you balance scrapers with dozers to get the most production out of both? When do you decide to add another scraper or another dozer (either for pushing or grading/smoothing)? Thank you in advance, I'm trying to learn as much as I can about earthworks and excavation
There's a lot to consider when deciding if a pan/scraper is the best way to go. Scrapers aren't a good choice for rocky, rough or steep terrain. Excavators and off road haul trucks are better for those conditions. A tractor pulling an open bowl scraper is good for sandy soil or dirt that's been loosened with ripper or plow. You can also top load an open bowl with an excavator if smaller size rocks are in the dirt but you can't "kick" those with a dozer. I used to work on large JD articulated tractors that pulled two 18 yard bowls and they will move a lot of material but are expensive and have to be top loaded unless the dirt is loose and not very rocky. Self loading scrapers do a good job in the right conditions but not good for wet, muddy or steep terrain and the elevator chains, paddles, etc. are high maintenance items and are usually in the 12-16 yard size which is not a lot of capacity. The new vs. used decision is a tough one as well. New equipment is extremely expensive and used equipment that's not totally worn out is hard to find and repairs are a much bigger issue than they used to be. Most of the time getting equipment on an RPO contract (rent with purchase option) works out better for risk management but I'm much more geared towards the repair/maintenance side of things. I think your best option is excavators and haul trucks for versatility instead of scrapers and the haul roads don't matter near as much. I see you're in Texas and I'm not familiar with that part of the world. I'm in central N.C. and a lot of contractors I've worked with in the past have parked 621's iand comparable machines n favor of haul trucks and excavators. I know a lot about fixing pans but you might want to see what's being used around where you plan to work to help you decide which way to go, the contractors who have been around for a while are the best example to look at. Good luck, hope this helps a little at least.
Thank you for the insight. I’m in Houston where the soil is very sand and clay heavy. The super I shadowed with described how his tractor pulled scrapers were a lot cheaper to run than trucks + exes, and kept his company competitive. I never heard of scrapers before I went with him, so I’m trying to learn as much as possible. As for here, the ground is pretty soft. Houston is an extremely flat area, and even the areas an hour or two from here are just about as flat as where I’m from. There aren’t really any rocks or grades to worry about, which is probably why running pans works well here. Also, could you run dozers to both clear topsoil while also ripping the ground to prep for pans, or is that best to separate into 2 different actions or machines? If I had tractors out, I could also see using a plow, and it might be more efficient that way, but it’s another attachment to buy/rent and transport. As for using ADT and exes, when he described it being more expensive, it makes sense because you’re paying for 2 operators and 2 machines, and cycle efficiency is lower because they’re both dependent on each other. It could be that off road trucks are the best in NC and not here. Would you mind sharing the production rates you get with haul trucks (YDs/hr)? Your post is very helpful, I’m going to write down what you said
There are lots of videos on scraper fleets in action. Here is one. I've seen fleets working glacial till, shot rock and mixed sand and gravel. I've been told that there is no cheaper way to move earth than a scraper show. The issues now days are the initial cost of the machines and that there is only one real manufacturer of large motor scrapers. There are or were a couple of construction companies running 631 and 641 units that were single engine units that were pushed by dozers to get big production. Most of those were B, C and occasionally you see a few E models. The landfill business generally runs 637 twin engine units. These units usually are push/pull machines but the land fills generally don't get the machines with the front bails installed because they only run one machine. The large California companies run with the bales and in paired machines. One loads while the trailing unit pushes and when full the trailing unit is pulled by the front machine. They separate when both are filled and proceed to the spoil area. All those operations that I seen use a dozer pushing both scrapers to load. There will be other dozers ripping at the same time. I have seen scrapers working steep ground as well. Check out this video I shot years ago: This is a large contractor still in business in Western Washington State. The machines in this video are between twenty and thirty years old at the time it was shot. I'm living outside of Coeur D'Alene Idaho now and that the same company is working a section of freeway improvement on I90. They current are running six 631E units as far as I can tell. I do see some of what I call the oddball scraper shows using elevating and even one auger unit. Those I've only seen on small construction shows. I don't believe them to be high production units. I've never heard of anyone push loading these units. There was a small construction company some years ago using pans pulled by articulated tractors in northwest Washington State. They were around for a couple of years and then seemed to fade away when a down turn happened.
50 yr old machines that keep the new honest.
Scrapers are a great way to move dirt Here the see diverse conditions from clay to shot rock quite a few outfits here are running them There is 1 outfit with tractors and cans and a few guys are trying out artic with a can but the work areas are limited Tractors and pans will go thru sand a scrapper never will
The sand operation that did a property swap with me had a contractor come in with scrapers to build up an area around their scale house. The guy I always dealt with was amazed how fast 627's/637's were in the sand.
A fun fact Dave. A Wabco 222 is ⅓ faster in all aspects of dig, haul and dump than a 627. Maybe your mate has never seen the comparison.