---In STMFC@..., <Rhbale@...> wrote :
You are looking at a Bettendorf L-section 30-ton caboose truck manufactured by the Bettendorf Axle Company of Bettendorf, Iowa. The L-section is a clue that it was likely made between 1903 and 1908. After that date most Bettendorf trucks were cast with T-section frames. By 1920 almost all had U-section frames which is still used today.
I completely disagree. Both the 1909 and 1916 CBC show drawings of the Bettendorf swing motion caboose truck of the time, and they have T section sideframes. Furthermore, they have structural steel (channel section) transoms riveted to the side frames. The unitized floating bolster package, which the truck Chuck is showing us has, was a later development. The truck in Chuck's pix is likely one of the last iterations before they went to a U section sideframe, and likely dates to the late teens. The U section sideframe is first shown in the 1922 CBC, IIRC.