Troublesome Tanker Question

i believe blank white tanker cars do exist.

On the other hand, there's a good supporting cast there - Thomas with a white running board, three green spring-loaded bolster flatbeds, three open trucks of the right colours, and another that could be a brown SCRuffey, green crane. In fact all the main components of the correct Thomas Freight Cars set apart from the red & white coach. That's why I'm optimistic.