Bottom-dump configurations also include a three-axle semi-trailer version with a six-axle pull unit, and a two-axle "Light Weight Aggregates" version with a three-axle pull. End-dump trailers in Beall ...

"That is when you find that a shorter multi-axle dump trailer is better." Longer 39- or 40-ft. dump trailers are typically configured as five-axle rigs — three on the tractor and two on the trailer.

Taylor Services Inc. also runs 39-ft. end dump trailers, but claims the straight trucks are a safer alternative. "From a dumping standpoint, it is much more stable than a tractor/trailer.