The plausibility of such machines has declined with the advent of the real-world tunnel boring machines, which demonstrate the reality of the boring task.
The depression of 1930-39 demanded rigid economy and required individual financial aid to tide over some unbalanced budgets, but curling never declined.
In the latter half of the 19th century when the railways came into existence, the significance of waterways as inland trade routes declined, as the railways were faster and safer.
