@mark s posted:
Santiago: ...snip... One of those O1a's has been preserved in Mendota, IL (#4978, with Elesco feed water heater. That specific locomotive was done by Sunset 3rd Rail).
I took these on a 2015 visit to Mendota when attending an event at Sandwich, IL. That little museum is quite an interesting place. When I was there, they offered rides on a track car and trailer; not to bad for (at that time) around $1.50.