Sometimes, yes - more often they result in cronyism and officials and bureaucrats amassing power to trade for $$.

Since you brought up trains, look at the giant mess that is the California 'bullet' train. Not a single section of track has been completed, and it's already doubled in budget, reduced dramatically in speed (current projections put the trip time at ~4hrs due to a number of issues including track sharing), with ticket prices 70% higher than promised, and the legal requirements for private investment have been ignored because no private company is willing to touch it with a ten foot pole.

Dramatic changes indeed...