In this video, we see 3 different classes 'in steam' at Ambarawa. The E10 (E10 60) was still at Ambarawa prior to going back to Sumatra, the C12 (C12 18) had been moved here from Cepu to be repaired but was not quite operational (but was in steam at least at the start of the sequence) and B25 03 used to both drag the C12 and for a run up to Bedono and back. I don't know how many years it was possible to see E10 60 and C12 18 together at Ambarawa but surely not many before the E10 returned to Sumatra and the C12 moved to Purwosari to operate trains to Solo Kota. Incidentally, the E10 never went up the rack at Ambarawa (as far as I know) as its rack gears weren't compatible with the Ambarawa rack.
