Uhhhhhhhhhhhhhhhhhhhhhhhhhhh.... railgun has a 600m hard-capped range. Missile is maybe a third of that.

For fighting enemy tanks, and ONLY enemy tanks, the Railgun has huge burst damage, and can often crack an enemy tank open before they have time to pop their actives if you catch them off-guard.

If you want better infantry options, and a bias towards anti-armour (which are the most popular anti-infantry tanks), then it's probably worth bringing Missiles.

If you plan to disregard infantry, Shield tanks have the best resistance against most hand-held AV weapons currently in use. If you notice your shields starting to drop, and it's not because of an enemy vehicle, popping a hardener makes you near-invulnerable. If it's a Forge Gun or a vehicle, it's worth considering a second hardener (if you brought one). Armour tanks are better for actively fighting on the front lines, because they have the larger raw HP pool to work with, but the damage they take from well-placed AV infantry can help to balance that out if your tank doesn't have good infantry support.

If you really want to find your niche, and you're leaning towards Missiles already, train up JUST enough to run the Standard Large Missile Turret, then experiment with Militia versions of EVERYTHING - you can build a Sica and/or Soma with any weapon set you want EXCEPT a Large Missile Turret without needing to invest any SP into anything vehicle-related. Skilled tankers will dominate you if they see you coming (and actually skilled tankers as opposed to "skilled because SP" tankers WILL see you coming), but you should be able to get a feel for what your tank does and how it performs with the various options available.

As a long-term consideration, it's worth skilling into at least a couple of different tank setups so you can handle varied opponents, rather than sticking to one possible role and only reall ybeing useful when your ideal target is on the field.

I recommend a shield tank for your needs, mainly because of the increased maneuverability (very useful when using a rail). Also because armor tanks have a hard time fitting missiles because of the high cpu cost

Yeah, Missile turrets will break your heart when it comes to fighting Infantry. You'd think there'd be raw chunks of meat spilling in the air, or something. The irony is that small missile turrets are devastating against infantry, but large turrets are a blind exercise in dumb luck.

Rails on the other hand, get the job done nicely. It's an automatic one-hit kill too. Lining up the shots can be a chore, but the accuracy is such that if your gun-sight turns red, you're guaranteed a kill. I'm only good at picking off stationary targets. I've heard Charchar odell, and Void echo can rail moving infantry, though. Sounds pretty bad ass.