Wrong. It flooded the network with vacationers who normally could not afford travelling at all, while workers had to resort to their cars again to reach their jobs in time. Counting everyone who "would not have travelled by train", meaning "likely not at all" as saved emission is not very convincing.
According to the article, the study accounts for this. Do you have some evidence that it does not?
Can you please point out the part of the article supporting this claim?