"Mary had a riddle lamb, brain-tease was hard as stone!"
Today Mary's lamb wants you to solve its riddle.
A white man plowing the dark soil
Silent oxen around him toil
A train whistle is near
What's said may disappear
Half hint:
The lamb isn't involved, that's just the name of a series of riddle.
Hint #1:
Caius Titus dixit