I just found the following reference of a Pioneer Corp in Chapter 5 page 82 of Edward Young McMorries' book "History of the First Regiment, Alabama Volunteer Infantry" written by him in 1904 who was a private in Company G.

He is talking about the 1st Alabama crossing the Tennessee River and marching toward the battles of Franklin and Nashville in late November and early December 1864.

"The fourth day after leaving Florence, we came to a large creek with a narrow valley walled in on both sides by high precipitous hills. The regiment marched up this creek the whole day, crossing it fourteen times on rude bridges hastily constructed by our pioneer corps."

I am not sure of whom he is referring to. This could be some designated people within the regiment or it could be some organization within Hood's Army.

I hope this helps.

Randy