Very nice! Buddy of mine worked on an aircraft carrier. Good job on the steam. It's kinda scary if you think about it that a steam-powered launcher is still the best way to launch an aircraft in such a short space. I like the "Get Some!" message next to the munitions. I do hope I'm not on the receiving end of that. Excellent work on the perspective. It gives great depth to the image.
Electromagnetic ones? Interesting. It's like shooting a plane off using a railgun.
However, you cannot overlook the dramatic effect of the steam from the old school catapults. It's quite high on the awesome scale. Unless we get electric arcing and sparks, the railgun is going to be nothing but a bunch of boring art/photo wise.