Yes, I occasionally run steamers solo. Running this way adds a nice variation to my "normal" railroad operations. I run my Williams scale B&O 4-6-4 hudson ( painted in Blue ) this way, & my Williams scale camelback mostly. I also run GG1s this way from time to time.
As a kid I had the opportunity to watch Pennsy trains on the main between Philly and Baltimore. Wow .... the parade of trains I saw was spectacular!!! Fast passenger trains with GG1s heading south and north, followed by a short freight local with an end cab switcher heading north, long freights with several GP 9s heading north, a solo end cab switcher heading south, another long freight with two GG1s at the point, a short passenger train of MU cars, a couple GG1s deadheading somewhere, a work trains pulled by an alco RS 1, a long freight pulled by F units, a solo RS 3 heading somewhere, Fast mail trains pulled by E 8s, etc, etc, etc. ( I may have seen some bigger boxcab electrics as well ) It seemed I saw a train every ten minutes or so and the parade and variety was endless ( as only the Pennsy could provide ). I especially loved the solo locomotives because they would put along by themselves providing a punctuation of relaxed contrast the faster and longer trains. The solo locomotive moves provided greater depth to a great day of train watching! I have never forgotten this and have always incorporated this kind of running into the operations of my own layout.
Too bad steam on the Pennsy was gone by this time so I never saw any Pennsy steamers run solo or otherwise.