It has been confirmed that Amtrak has relocated the train director(s) working K TOWER at Washington Union Terminal from the historic 1908 structure and into a small office in the Railway Express building adjacent to Track 29 on Union Station's lower level.
Unlike R Tower in Sunnyside yard, where a similar relocation immediately preceded demolition to make way for an Acela maintenance facility, the historical significance of Washington's K TOWER is well understood. In 2017 I reported on plans to cover over the entire union station approach with some mixed use development with K Tower specifically singled out for conversion into some sort of high end bar. The culprit here is some combination of Amtrak's desire to simplify "management" and also cut costs along with some technical upgrades that were evidently completed behind the scenes.
As constructed in 1908, Washington Terminal was controlled by at least three US&S Electro-Pneumatic equipped towers, A Cabin, C Tower and K Tower. In the 1970's, K Tower had its long Electro-Pneumatic machine replaced with a then cutting edge N-X type interface and model board that drastically cut the need for staffing (and floor space) and centralized control of the entire terminal into a single location. This change likely took place around 1975 as the construction of the DC Metro's Red Line required the demolition of C Tower. Although cutting edge for the 1970's, by the 2010's the N-X machine was becoming increasingly difficult to maintain as parts were long out of production and failures could become rather nail biting in terms of getting the machine working again.
Although decorated with some LCD screens, the big old N-X panel's days were numbered and as soon as the control was converted into a video display interface, the human train director was no longer limited to being in the tower itself, especially if CCTV feeds could be provided. Although I suspect the historic K TOWER will be maintained and serve a railroad function, while active as a work site the HVAC, restrooms, etc would all need to be maintained to a higher standard. Plus there is the added benefit of management being able to "pop in" to "supervise". It is quite possible that the N-X panel was actually replaced years ago and COVID simply delayed the inevitable. K Tower would therefore be a rather extreme example of a "return to the office" policy. Still, given that computers can be installed anywhere, there is always the chance that the K TOWER staff could find themselves back in the old tower in the future, baring some redevelopment effort.
K TOWER joins the fate of many other pre-video "panel" type interlocking setups that I discussed previously in the content of Hoboken's rather short lived TERMINAL TOWER. Given the ease at which an N-X panel can be converted to a video interface, it is entirely possible that, rapid transit systems not withstanding, we might see electro-mechanical machines outlast hard wired N-X panels in staffed towers.