I recently found a photo of the Ampol No.3 tanker on 24 April 1965 (right in my era) in the Train Hobby Blayney/Cowra Branchline book (page 21) and noted that it had a petrol spill from one dome. Here is an extract from the photo showing the spill. There is also another photo of the same train earlier in the book.
I decided that I would attempt to replicate this and here is the result.
I first gave it a dusting of a pale yellowish brown and then airbrushed some clear gloss in the appropriate area. I didn't use a brush as I felt that it would give too sharp an edge.
Unfortunately my air brush decided to spit and I ended with a couple of tinydrops when doing the dusting, oh well it still looks good.
But it could do with a bit more clear as this closer shot shows.
Here it is with some more petrol stain (clear), the spatter can be seen under the walk way below the first dome.
Morpeth Video Update #1
17 hours ago