That depends on what you mean by Union troops in the West. Supposedly, soldiers in Grant's/Sherman's/McPherson's Army of the Tennessee preferred slouch hats; whereas Buell's/Schofield's Army of the Ohio and Rosecrans'/Thomas's Army of the Cumberland were more like the Eastern soldiers and wore a high percentage of kepis and forage caps. Yakey and his silly Whipple cap in my above post was in the Army of the Tennessee but that photo was taken early in his enlistment in 1862 before such things were discarded and replaced by something more practical.
Maybe Hooker's XX Corps, transferring from East to West, but in most images of Army of the Cumberland troops I have seen, they are primarily wearing Hardee hats and slouch hats. The first images posted in this thread, whether the 21st Michigan or 44th Indiana, both served in the Army of the Cumberland.
Here's a series of photos of the 125th Ohio Vol. Inf. "Odycke's Tigers" taken at Nashville, June 1865. From
The Photographic History of the Civil War, vol. 3. The 125th Ohio served in the Army of the Cumberland from 1863-65.
Company H. Captain Anthony Vallender at center.
Company C
Company B
The Tiger Band. Musicians of the 125th Ohio regimental band. Principal Musician Samuel Sidlinger at far left.
Also had this one saved, from
Echoes of Battle: The Atlanta Campaign. Color Guard of the 10th Kentucky Vol. Inf., which primarily served in the Army of the Cumberland.
This one has been posted here before, but there's some more to it. Color Bearer at center is Cpl. Orville B. Young.
In Col. William H. Hays'
official report of the battle of Jonesborough, Sept. 1, 1864, he says: "Corpl. Orville B. Young, the color bearer, deserves special mention for the manner in which he discharged his duty when the regiment was checked by a murderous fire within twenty yards of the enemy's works. He ran forward with the flag, calling on his comrades to rally to it. It was the first flag placed on the enemy's works."