Instead of relying on vehicles and forward raxes I think it would be cool to have com-buildable train tracks, where all you do is place two 125$ res station buildings and place 5$ track sections between them (which do not have to be built by engineers) and then a train vehicle would appear on the tracks, and you can buy more trains in the station for 400-700 (depending on how you arm it.) These trains would be heavily armored and could have capabilities of carrying pretty large weapons, but are limited to where they have tracks.
Yes, trains would most likely share research with other vehicles. To expand on my shitpost suggestion, there would be three varieties of trains: Defensive weapon trains, which could be heavily armed (about equivalent to the factions heavy tank, but with 8 plates of max armor), Supply trains, which resupply any tank within a significant radius of them (can get a 2slot mg and a 1 slot cannon/ml, 3 plates of armor), and personnel trains (apc on rails, can get ugl/3slot mg, 4 plates of armor).
I kinda think this is neat, maybe make it so you can build the rails up off the ground and make some loops and stuff. In short, I want roller coasters.
This is less about thread derailing and more about train derailing. We could have some trains that are good at being on rails. Some that can do both and some that are best when they are freely moving off the rails. I'm still not sure what could move something train-sized across open ground, but it'll come to me soon.
BigTeef: STAHP, this idea is bad. Trickster:mmm, it's good. edit : http://en.wikipedia.org/wiki/Railway_gun dayem.