Seven factions, two wars, one battlefield. Devastation is IMMINENT...
While infantry isn't really something the Soviets depend on that much, these vehicles can help provide tank battalions with some much needed infantry support. The Flak Track is now a dedicated anti-air vehicle with limited transport capability, being able to transport two infantry or one large infantry. Its also armed with a 12.7mm DShK effective against infantry and it's on-board radar can detect stealth units.
The new Sickle APC takes over the Flak Track in rapid infantry deployment roles, being a fully amphibious corkscrew drive vehicle with the capability of carrying five infantry. Its armed with a pair of Kornet missile launchers which is decent against vehicles and structures, making them handy fire support for your infantry platoons.
credit: Issly (Sickle APC), Bu7Loos (Flak Track)