It goes against pretty much everything in the zeitgeist, but yeah, men and boys are really hurting from this lack of all-male spaces. I hope culture boomerangs around enough to permit them sometime soon.
That's pretty much the kind of thing that is available for men.
Obvious disclaimer: there are plenty of women who like trains, electronics, shooting, cars and other stuff, but that doesn't change the very high chance of finding the romanticized "all-male-space" if you show to a rail fan meetup.