This condemnation is nothing more than high stakes poker between RTD and the current owners of the building. Obviously there is a disagreement on price and RTD has decided they are not going to wait any longer.
After having been involved in a project in Dallas that involved former Katy Railroad land now owned by UP, I would suspect that some of the DUT ownership was Rio Grande (later SP) and there are valuations claimed by UP at the time of the merger that in fact may be way over what the land is worth in today's market. Obviously UP is not going to step up now and admit property is worth less than what was paid for it at the time of the merger.
In the Dallas case, there was ground pollution involved and that eventually killed the deal as the two sides disputed what needed to be done for remediation.
In short there is probably not a lot of the complications that we know about.