That machine was used to cut t-slots in K&T tables.It was built, I believe,just prior to WW2.Kearney&Trecker built a series of small planer mills to process their tables.They were in service until 1980 when all standard machine production stopped.
I was working in the next bay from the table department (035)in 1979.At that time they were running TF and S series tables.
In 1986 I was working in the rebuilding division.They had one of the bridge mills from the table department.It had two vertical milling heads on the rail and one horizontal head on each side ,mounted on the columns.
It was originally used to mill the dovetails on the bottom of the tables.
The horizontal heads milled the font and back faces and cut the auto-cycle t-slots.
It was a nice machine to run,but its work envelope was small, due to the purpose-built nature of its design.