Where/when did these run, just out of curiosity?
1948-49 was an interesting year. If you wanted to go from Chicago to Seattle, you would ride the Olympian Hiawatha, train 16.
You would leave Chicago pulled by a trio of Erie Builts if it had extra sleepers, or a pair of A-A Erie builts if it was a lighter train..
Then, when you got to electrification, your power would switch to a Quill (big electric box-cab).
Then to the "gap" in Idaho where electrification stopped. It was night time, and a big black steam loco pulled you.
Once the gap was crossed, electrification picked back up again in Othello Washington where an EP-2 class bipolar electric took over and took you all the rest of the way.
To my knowledge, this was the only train that was pulled by all three kinds of power (diesel, steam, and electric) all on the SAME train.