Mainline was a very short lived line, but a storied one anyway.
First though - wow, what a cover! Remember that the Korean War had only 'ceased firing' in the summer of 1953
This is only a few months after the 1954 Senate Hearings on #juveniledelinquency with Wertham and Gaines and would have a historic impact on the business of comic books
On watching Gaines testify, Simon chided "stupid, stupid, stupid"
The printers needed material to print
Is Mainline the first Creator Owned company?
I'll ask @ErikJLarsen
However, there is a review of Foxhole no 1 (and others) at the Jack Kirby Museum.
kirbymuseum.org/blogs/simonand…
In the section for 50 Best Kirby Covers, Foxhole 1 was chosen by Mark Evanier and Bill Morrison. That cover stopped me in my tracks