Valvegear, you are correct.
DERM 60 has departed Melton Station and drops down the grade towards the Melton Reservoir steel bridge at 3:20pm on Tuesday 12th June, 1979.
My younger brother and I had been taking some photos of trains at the large bridge over the weir and were walking back to Melton station to catch the next 'up' train so we could get back home to Clayton.
DERM 60 was running a 'down' Bacchus Marsh pass and we had to make sure we were back at Melton to catch it on the 'up'.
We arrived at the station with about five minutes to spare.
I was 16 years old at the time.
Over to you.