Galveston: What we saw on the drive

One quick thing I can post. Both on the drive to Galveston and the drive back, we saw perhaps a dozen large trucks carrying some long, odd-shaped pieces that I couldn't identify. My best guesses were airplane parts, some type of piping, or parts of a water slide. On the way back north, we snapped a few pics, although the angle makes it difficult to see exactly what we were photographing. Anyone care to venture a guess as to what these trucks were carrying?