The Model 1885 Trousers are made from a medium blue wool. For mounted troops of all ranks, the trousers had leg seam and seat reinforcements sewn in to protect a rider from chafing. As a mark of rank, the trousers had a wool stripe sewn on. The stripe's width was determined by rank or duty: all "Big Three" officers had a 1.5" wide stripe, while other officers had none; Sergeants 1.0" wide; Corporals 0.5" wide; and Musicians had two 0.5" wide stripe spaced 0.5" apart. For the "Big Three" branches, the color of the stripes were white for Infantry, red for Artillery and yellow for Cavalry. For other enlisted troops, the stripe's color varied depending on the assigned branch, and was often piped in a contrasting color, i.e. engineering troops had stripes of scarlet piped in white, et cetera.
U.S. Army Quartermaster Department, Regulations and Decisions
pertaining to the Uniform of the Army of the United States, Second
Edition, 20 June 1898, (Washington, Government Printing Office, 1898).