I don't know about where you are, but here at least, engineering isn't such a conservative field. My grandparents are always pointing out that the country is "crying out for female engineers". One company who trains their apprentices on the same site as me have a ridiculous number of girls in comparison to us, and when I considered applying to them one my lecturers actually pointed out that I would be at an advantage due to my birth sex (he didn't know I was trans). It's pretty obvious they were deliberately recruiting females.
On my course there's 9 girls plus me, so they didn't go out of their way to get females, but at least 4 of them are people I would class as "girly". One of them is doing one of the most physically demanding jobs in the company. They are very interested in why we chose this field though, which grates me a lot, but I stay out of it and answer as I could if there was no question about my gender. There is an out trans woman here, and someone who's family has worked here for generations reckons that there are lots of trans people.
I'm not out here for several reasons, mostly because it was a rush as I was originally rejected/put on a reserve list. I didn't think I'd be able to come out to my family, and convince them that I was sane enough to move out into a completely new environment before I had to leave. It doesn't help that I don't know how they would have arranged living accommodation for me as we're put into shared rooms. I am planning to come out later though, once I get out of the gender segregated rooms.
Sorry I couldn't be more helpful, as I only have experience for two companies and haven't come out here yet, but everyone in the UK seems to love female engineers. I have to admit I did use that to my advantage. It's just another little thing that makes you stand out. If you have protection against discrimination where you're from I'd apply as female, and once you're hired, come out.