"When" clause in second conditional

I would like to ask you for clarification, if the usage of the when clause is correct in the second conditional.

In one book I found the sentence:

When the factory came online in 1990, he would control the best factory in the world.

The first part of the sentence - When the factory came online in 1990 - never happened.

Is the when clause correctly used instead of an if clause?

Without knowing the context, it seems to me that this sentence is more an example of reported thought than the conditional. I assume that the author of the book was writing about the time before 1990, when the manufacturer had a firm plan for his factory to go online in that year.

The manufacturer's thinking, pre-1990, was:

When the factory comes online in 1990, I will control the best factory in the world.

This thinking was backshifted in its reporting by the author to:

When the factory came online in 1990, he would control the best factory in the world.

A dependent clause starting with if rather than when is also possible. But it would convey a doubt about the realisation of the plan, which the manufacturer presumably did not have.