MSW Management | It’s Hard Out There for Transfer Trailers…and Their Delivery Mechanisms

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There is one great, overlooked component in the whole mix of MSW work.


	Grizzly Bear Alert

With few moveable parts to contend with and perhaps even less to think about with new models and high-tech developments, there’s not a whole lot to consider about transfer trailers in the short term. But operators and dealers around the country still have plenty to say about how they’re using this equipment and how it’s holding up.

Lots of Traffic
The Three Rivers Solid Waste Authority (TRSWA) is a relatively new MSW handler, covering a nine-county area in South Carolina. The TRSWA has some 40-plus transfer trailers actively hauling waste each day. It replaces two or three trailers per year with new ones. It is currently in the process of placing automatic hydraulic and electrical tarping systems on a number of them. The tarps themselves are constructed of a nylon screen material.

“That’s probably the biggest change we’re currently going through,” says Brent Allen, director of operations and landfill management. “All the new trailers we’re ordering will come with new tarping systems on them. These are mainly just to keep our workers safe: It’s fairly precarious hand-tarping trailers. Also, our new automatic tarping systems will save us time. Our trailer tarps are made by Sidewinders and Arrow. One is electrically operated and the other hydraulic.

“Our trailers include a good variety, including, among some others, J&J, Fabrex, East, Travis, and Stecos. We’re part of a municipal government; therefore we approach manufacturers who give us the lowest bid and lowest price. They’re required to at least match specifications for our equipment.”

The TRSWA uses all-aluminum trailers in order to carry more waste material per load. “The downside of aluminum is that we do many repairs on metal-fatigued areas and center bars simply because these trailers aren’t as rugged as a steel trailer. It’s a trade-off. But we’ve stuck with aluminum live-floor trailers,” says Allen.

Most of the TRSWA’s live floors are manufactured by Keith Walking Floor of Madras, OR. “Most of the damage to our transfer trailers occurs at the transfer station, where equipment may hit a wall or a center bar gets pulled out by equipment being used to unload the trash,” says Allen.

Though most repair work is done in-house, the TRSWA will occasionally outsource the work, such as when a hinge has been knocked off. The challenge comes in managing the three or four trailers being repaired simultaneously, as well as all the parts involved.

TRSWA transfer trailers are inspected after every trip made. Preventive maintenance is performed continually to keep each moving part greased as well. Both the hydraulic system and the walking floors are continually checked to be certain they’re working properly. Major service is done every six months in order to redo brakes and repair air lines in the trailers.

A Long History
Haul-All Inc., of Lethbridge, AB, has worked for the past 30 years to design optimal transfer trailers and other collection and storage equipment for the MSW industry. This includes much work in research and development in order to find the best solutions for those out in the field. The company’s products—including various-sized units for handling waste—function in all sorts of weather. For many trailers a stainless steel option is offered. Stainless steel eliminates many of the undesired effects of salt and chemicals in the wastes handled.

“As far as going for the option of stainless steel, much depends on what material is going into the trailer; at times you have rather toxic stuff going into the wastestream,” says Dennis Neufeldt, president of Haul-All.

“The other thing is, if someone’s installing a long-term program it’s worth the initial investment to pay that extra and get the stainless steel. But the bottom line is we really don’t know how long units will last: We’ve been out there for 20 years, and most are still going strong.”

Haul-All offers a couple of 40- and 50-yard trailer units. Designed to be flexible, the containers feature a series of riveted panels, so it’s not a rigid assembly. “You don’t get the stress fractures that you would on a typical unit,” says Neufeldt.

“With our non-stainless steel units, it’s a matter of keeping paint clean so you don’t have corrosion on the surface. Most main bushings are the nongreasing type; there’s limited motion, so you’re not going to wear things out that easily. The units that we have replaced typically have been 20 to 25 years old.

“All we do is pull the old one out and place a new one in there. A look at the clock and how many cycles have typically been run usually tells us when a replacement should be done. Some are dumped once or twice a week while others may be dumped three or four times per day. Many different factors come into play, depending upon the trailer’s application. But after 25 years of use, significant metal fatigue may eventually occur, and often it’s time for replacement.”

In a Windy Place
Jackie Smith, public works director with the City of Cheyenne, WY, works with mainly live-bed trailers. “We have a transfer station in town, and the vast majority of our municipal household waste is picked up with packers and automated trucks, taken to the transfer station, and then placed in transfer trailers before it’s hauled out to the landfill,” says Smith.

“It’s 18 miles one-way to the landfill, through rough terrain, and normally each trailer makes two trips per day. In the summer it might be three trips per day. The landfill is north of I-80 on a two-lane road.

“But we don’t have too many problems with our trailers. What wears out first is the walking bed. Just two years ago, four or five of these were rotated in to be rebuilt.”
The biggest environmental factor to deal with, according to Smith, is the wind. “When the wind blows at 30 miles per hour for a whole hour, we have to shut down the landfill. Such winds affect us some 80 days out of the year,” says Smith.

“On occasion we’ve had to store trash up to three or four days before we could take it out, due to snowstorms, blizzards, or severe wind. In the middle of the night, winds may die down enough so we can do the dumping. Guys spend a lot of time, especially in the winter, going out into the bitter cold [whenever the wind allows]. Winds are especially bad in the winter. During half the days in January, wind speeds regularly exceed 50 knots at some point in the day. ”

Cheyenne uses Load Runner Trailers, manufactured by Wilkens Industries of Morris, MN, for its MSW hauling applications. These trailers have hydraulic screens covering their loads.

“When we get ready to unload, we can raise the screen to the proper increment to let the load clear out,” says Dan Beard, director of fleet maintenance with the City of Cheyenne. “Our Keith Walking Floor walks the load out in a minimum amount of time, with the screen preventing junk from flying out the back of the trailer.”

Earlier operations used mechanical screens, which had to be either opened or shut. “We had concerns with those, though, with people having to climb up there for various operations and then getting cut,” says Beard. “Now we’ve solved three problems: Our workers are away from blood-borne diseases; they’re kept from having to go up there during a high Wyoming wind and getting blown off; and we can now lift the screens independently from front to back and they cover half the trailer. We raise them both to whatever angle we want them.

“On a nice, calm day we can open them all the way up. As soon as unloading is complete, we drop the screens back down. Before we leave the transfer station the screens are fully closed—not airtight—but they do keep the trash from flying out. We have five of these transfer trailers, all with these pliable nylon fiber screens. The material holds up so well, I’ve never had to order any more of it.”

Cheyenne uses aluminum trailers. At times the frames on their trailer screens crack, according to Beard. “If material becomes lodged in our trailers, it cuts the panels or screens open. In those cases we’ll weld the damaged metal on the panels back together; if the damage is too bad we’ll call the manufacturer and have them replace the panel.”

Beard trades in trailers to get different types, if necessary. “I’ve also sent our trailers up to Wilkens and had up to four rebuilt, getting new sides, braces, and floors—everything but the undercarriage,” says Beard. “As far as costs are concerned, I consider the upgrading or ‘kitting’ of a trailer to be one way to change a 1989 model into a 2006. It can be done with a truck as well as a truck trailer.”

Beard had some concerns about the Walking Floors at first. “We were worried they might freeze up in the cold weather,” says Beard. “But what we do now is, if they set overnight when we arrive for work in the morning we’ll shake them, meaning we’ll run them with no load on them to make sure they’re loose. Then when we run loads on them there are no problems.”

Beard has never had a problem with the suspension systems on his trailers. If there ever is a problem, parts for those are available locally.

The city has four 25-yard packers for a total capacity of 100 yards. The landfill’s compactor weighs 119,000 pounds. The operation used to cover each day’s fill with soil, but it no longer does things that way. Now the facility has an automatic tarping machine by Tarp-O-Matic Inc., of Canton, OH. With its heavy chain inside, this tarp is laid down each night to hold garbage in place. In the morning a machine rolls the tarp back in place. “This way we save 6 inches of dirt that we used to have to cover things with, each day.”

Floors for Loads
Hallco Manufacturing Co. Inc., of Tillamook, OR, manufactures live floors for tracker trailers and bin applications. One of the main things it does when its equipment is outfitted at an installation is to have a “floor school,” which can be requested by any customer. The floor school teaches how to both install and maintain the Hallco equipment, including how to keep it running efficiently and clean it out.

“This class is run for anyone who wants to know how to run our live floors most efficiently. In the long run it really helps a lot,” says Barbara Hurliman, marketing manager with Hallco. “We have three different facilities, in Oregon, North Carolina, and Texas. In our North Carolina office we have a service truck which goes out to conduct the floor school.

“In addition to this, we’re starting a pre-maintenance program where companies can come in and we will help with all sorts of maintenance, from changing oil to tightening bolts—anything to keep their equipment running in an efficient manner. Such actions save lots of money over the long haul.”

Applications include mill operations and bin applications. A local Oregon operator actually uses the product in the course of hauling sawdust for farming operations. Products from grain to sawdust to garbage can be worked with, according to Hurliman.
“Some of the trailers have an open top so they can be unloaded for garbage,” says Hurliman. “In those trailers we have a heavier floor; they can take the weight of the pounding. Things such as grain and other commodities don’t require such a heavy floor.”

With the garbage application especially, maintenance needs to be a top priority. “That’s basically the way it is with anything out there,” says Hurliman. “Keeping things clean is key, and a regular cleaning program helps. We have a leak-proof floor which helps with both the MSW industry and in transport of silage as regulations for leaking onto roads are enacted.”

Most of Hallco’s systems mount beneath the trailer or on the front of the trailer. With a full pan placed underneath the floor, all water and moisture can be self-contained. Sealing off the front of the trailer keeps leakage from occurring there.

“Our competition is dumps and tippers,” says Hurliman. “At the transfer station, if there are 10 tippers waiting, you’ll be waiting for each of those systems to unload. But a live floor can unload at any time.

“Also, if the weather is bad and the wind’s high, tippers can’t be used. Our equipment, however, can be used at any time. Indoor dumping facilities can be problematic for tippers because of low ceilings, but our live floors work fine in those, too, even loading onto another conveyor taking it in to be sorted.”

The floor slats move by hydraulics, all moving to the rear of the trailer at one time, 10 inches per stroke. “It unloads very quickly, and then the truck can move forward,” says Hurliman.

“Perhaps the biggest problems can arise from not keeping things clean underneath the trailers where our floors are mounted. The floors do best if protected from abrasive road salt and gritty sprays by regularly washing those surfaces off. Our floor schools teach and demonstrate all of this to get the word out on use of the product and maintenance. We even show how to do rebuilds on this equipment if they need to after a few years.”

The floor slats are constructed of aluminum. Different ones are made for different applications. Hallco systems have life spans often outliving that of the trailers themselves. The company sells replacement parts for all of its systems.

Mechanic-Friendly Is the Key
Jason Proctor, owner and director of operations of the Proctor/Crookshanks Companies in Corcoran, CA, uses the Hallco Live Floor. The business runs about 100 trucks in operations including livestock hauling, food-grade oils, cotton, and agricultural products grown in the San Joaquin Valley, in addition to its MSW applications.

“The greatest asset of the Hallco product is that it’s mechanic-friendly,” says Proctor. “It’s much easier for our mechanics to work on the minor components. We’ve also found the Hallco product to be more durable for hauling, especially in California, where restrictions and regulations are among the toughest in the nation.

“Any manufacturer of such a product has a real task in building a product that will hold up in this industry; Hallco’s done a darn good job. We see a big advantage in the electronics and the valves [related to] the hydraulic mechanism. With a Hallco you only have to change some small valves to accomplish the work, involving much less downtime.

“Hallco’s product has worked out best for us when it comes to maintenance, though both the Keith Walking Floor and Hallco are excellent products.”

Trailer-Maker as Customer
Keith Walking Floor likewise considers the maintenance on its systems to be low. “Our goal was to be maintenance-free,” says Dan Jackson, sales supervisor. “The main thing we focus on is getting the proper hydraulic wet-kit [pump, release valve, hydraulic reservoir, and components for supplying oil back to the system] to pull the trailer itself.”

As an example of how versatile the company is, it recently received a request for parts for a system built in 1975. “We were able to supply parts for them,” says Jackson. “We keep all of the parts in stock and can service our customers with dealers throughout North America and the world through what we call our stocking dealers. The Running Floor System II is an extremely simple system to troubleshoot—even sales guys can do it.”
In Canada, the trailers used tend to be fairly heavy stainless steel for strength, and weight doesn’t seem to be that much of an issue, according to Jackson.

“One of our biggest challenges is that we are in a number of different industries,” says Jackson. “We go to over 80 different trade shows each year, mainly because our product is in so many different industries. Fifty percent of our business is in solid waste, but we also do a whole lot with agricultural industries, forest industries, ice industries, and many others. Our chief part of the transfer trailer industry is supplying the unloading system. We chose to not compete with the trailer builders, but instead to have them as our main customers. That was one of the best decisions we’ve ever made.

“We have over 300 patents worldwide on Walking Floor technology,” says Jackson. “These have to do with valves, seals, bearings, and all of the components making up our system. We manufacture all of the components we use; there are only a few we buy elsewhere. Our machine shop is very sophisticated.”

Basic Maintenance Tips
Since 1989, the City of Bend, OR, has had some 14 trailers containing the Keith Walking Floors, according to Brad Bailey, general manager for Deschutes Transfer Co. (DTC). Unlike other regions in the Pacific Northwest, Bend stays fairly dry throughout the year, receiving only about 11 inches of annual precipitation.

“The Keith Walking Floor system is perhaps the least maintenance-intensive product that we own,” says Bailey. “It pretty much just works.”

DTC uses steel-constructed trailers for hauling primarily solid waste, though it does haul some compost and woodwaste. “It’s a staging of those cylinders on the Keith product that allow the floor to move under the waste in one direction without moving the waste, and then all moving together to unload everything in cycles. Likewise, material can be loaded onto a trailer using the Keith Walking Floor simply by reversing the process,” says Bailey.

DTC uses Star Transport Trailers Inc. of Sunnyside, WA, through Young Equipment. “Our landing gear and suspension systems have the most wearing out on them,” says Bailey. “Star has done some rebuilding of our trailers when it involves something directly with the trailer itself, but with most everything else we do the repairs ourselves in-house. The transfer trailer equipment we deal with is a pretty foolproof system for us. “The most important thing you can do maintenance-wise with a Walking Floor is keep your hydraulic oil clean. We service those annually; my guess is that you usually wouldn’t even have to do it that often, but we run a pretty tight maintenance program.”

DTC has yet to wear out one of its trailers, a fact that other waste handlers may find incredible. Some of the first transfer trailers DTC used were “pre-owned,” originating in King County, WA. “We bought those in 1989, and they were already about six years old when we bought them,” says Bailey. “They’d been hauling at least five loads per day prior to our purchase of them. We’re still running them today, with the original Keith Walking Floors in them. As long as they keep working we’ll stick with them. All in all, it’s a pretty rugged infallible system for us.”

Peter Hildebrandt specializes in science and engineering topics.

MSW - March/April 2007