You can just as easily paint this in a pragmatic light, rather than a sinister one. "We're going to clear some forest here where it's in our way, and to compensate, we're going to plant some additional forests elsewhere where they're more convenient" is very different from "we're going to spin up a forest-planting project so nobody notices we're cutting down trees elsewhere."
I'm curious if the new forest is actually a compensation that factors into the "diverting the railway is too expensive" math. Is reforesting actually part of the railway project's budget, or is it an externalized cost like environmental issues really are?
And even if it is included in their budget, are they accurately valuing an old-growth forest, or treating an acre of old-growth forest as equivalent to an acre of reforested area? I suspect if they put an accurate value on their old-growth forests and the ecosystems they support, then diverting the railway would look like the less expesive option.