Scale Ticket Doesn't Match the Axle Limits
A 48-foot flatbed is loaded with 24-foot lumber bundles totaling 44,000 pounds. The tractor has a 12,000-pound steer axle, 34,000-pound drive tandems, and the trailer has 34,000-pound tandems; gross limit is 80,000 pounds. The scale ticket shows steer 11,600, drives 35,200, trailer tandems 32,800, gross 79,600. The driver has four 5,500-pound working-load-limit straps and plans to use them. The lumber extends to the rear of the trailer but not beyond it. The trailer tandem slider is pinned near the middle of its travel and can move 18 inches forward. The driver is told to “just go” because the gross is legal, but a weigh station is 40 miles ahead and Maine spring weight restrictions are posted on a bridge on the route. The driver must decide whether to adjust the load, add tiedowns, or proceed.
1. Identify the legal weight problem and the most direct fix. Show the arithmetic.
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Gross weight is legal: 79,600 is under 80,000. The steer axle is legal at 11,600 under 12,000, and the trailer tandems are legal at 32,800 under 34,000. The drive tandems are overloaded: 35,200 exceeds 34,000 by 1,200 pounds. The fix is to shift weight off the drives and onto the trailer tandems, which have 1,200 pounds of unused capacity. Moving the trailer tandem slider forward increases the load carried by the trailer axles and reduces the load on the tractor's drives. An 18-inch move may not transfer the full 1,200 pounds, so the driver must re-scale and confirm. If the slider cannot transfer enough, the load must be repositioned or reduced. The driver should not proceed on the theory that gross is legal; axle limits are separate.
2. Are four straps enough? Explain the tiedown rules and the aggregate WLL.
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Four straps are the minimum number for this load, but only if each has a WLL of at least 5,500 pounds and the aggregate WLL is at least half the cargo weight. The cargo weighs 44,000 pounds, so the aggregate WLL must be at least 22,000 pounds. Four straps at 5,500 pounds give exactly 22,000 pounds. The length rule also requires at least four tiedowns for a 24-foot load: two for the first 10 feet and one additional for each additional 10 feet or fraction, so 24 feet requires four. However, the driver must also ensure each strap is rated, in good condition, attached to the trailer, and protected from sharp edges. If any strap is damaged or the WLL markings are missing, the driver needs more or better straps. Four is not a cushion; it is the minimum, and the load must also be blocked or secured against forward and rear movement.
3. What should the driver check after sliding the tandems and before leaving the yard?
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After sliding, the driver must confirm the locking pins are fully engaged and the trailer is locked in position. Check that air lines and electrical cords have enough slack and are not pinched, that trailer tires clear the frame and mud flaps, and that the slider mechanism is not damaged. Then re-weigh the vehicle; the scale ticket must show drives at or below 34,000 and trailer tandems at or below 34,000, with steer and gross still legal. Check bridge-formula or posted bridge limits on the route, especially with spring restrictions. Finally, inspect the load and tiedowns again, because moving the trailer can shift the load. If the re-scale still shows an overload, the driver must move cargo or reduce the load, not proceed.