ScraftyDevil
Banned
I've been considering Excadrill, but I was aiming for something that could easily switch to water/ice attacks to support Garchomp/Tyranitar. Excadrill is fast, but without good team coverage you can easily lose a match in Battle Subway.
Unfortunately you're kind of euchered, then. Very few Pokémon who benefit enough from Sandstorm to warrant a spot on a top-tier subway team are able to safely switch into both Water and Ice. The closest you'll probably get is Magnezone, who doesn't really benefit from Sandstorm aside from not taking damage from it.