![[Untitled photo, possibly related to: Chicago, Illinois. In the interlocking tower at Union Station. It is here that all inbound and outbound traffic is controlled. The men work entirely by the board, hardly ever looking out of a window to see an actual train]. Sourced from the Library of Congress.](https://images.rawpixel.com/image_200/czNmcy1wcml2YXRlL3Jhd3BpeGVsX2ltYWdlcy93ZWJzaXRlX2NvbnRlbnQvbHIvbG9jMjAxNzg0Mzg2My1pbWFnZS5qcGc.jpg)
https://www.usa.gov/copyrighted-government-workshttps://www.rawpixel.com/image/12290737
[Untitled photo, possibly related to: Chicago, Illinois. In the interlocking tower at Union Station. It is here that all inbound and outbound traffic is controlled. The men work entirely by the board, hardly ever looking out of a window to see an actual train]. Sourced from the Library of Congress.
[Untitled photo, possibly related to: Chicago, Illinois. In the interlocking tower at Union Station. It is here that all inbound and outbound traffic is controlled. The men work entirely by the board, hardly ever looking out of a window to see an actual train]. Sourced from the Library of Congress.
View public domain image source here
Public DomainFree CCO U.S. Government image for Personal and Business use