Hammerhead Gunship
The Hammerhead Gunship is the Tau's analogue to a Tank. Has a distinctly piscine name and can mount railguns.
It can be considered the Tau's "main battle tank", being a general purpose combat vehicle, though its mounted railgun means that it really shines against enemy armor. It has one point less armor in the front than a Leman Russ Battle Tank, but is otherwise similarly fortified. Unlike the Leman Russ, the Hammerhead is not intended to smash its way into enemy lines, instead hanging back and exploiting the 72" range of its primary weapon to put holes in the Tau's enemies while taunting them to try and rush it. It can be equipped with a disruption pod that gives it a 4+ cover save in the open and 3+ in ruins/fortifications that can help it remain much more survivable than its armor would suggest.
It can take an ion cannon in place of its railgun for a lower point value which will do some hefty damage to heavy infantry and monstrous creatures, but it is of questionable value for the point cost of the rest of the tank and the occupation of a valuable heavy support slot, especially since Tau have other options for doing so. Forge World makes some additional primary weapon options, which are much, much better than the ion cannon in every way, for the same price. Railgun, despite being quite expensive, does still manage to compete with the FW options however, due to it's flexibility. Secondarily it is equipped with either a pair of independently targeting gun drones, or a single smart missile system. The gun drones have a shorter range and pinning, but the smart missile system can hit from a slightly greater distance and ignores cover and line of sigh. Most of the time though this is moot unless in an emergency, since the Hammerhead will usually try to stay outside the range of these weapons anyway.