Station 51 Apparatus Continued... TACTICAL SUPPORT UNIT 551 is a 1985 CHEVROLET. Tactical Support Unit 551 has a cascade system that allows us to fill air bottles on scene. Tactical Support Unit 551 also carries spare air cylinders, salvage covers, electric generator, smoke ejector, saw’s and a multitude of other essential tools. REHAB SUPPORT UNIT 551 is a 1973 CHEVROLET. Station 51 is located at 8614 Southeastern Avenue. Indianapolis, IN 46239.