The Sanitation Subway Cart is your inverse car wash solution. It can be operated either on rails or on ground that could map any arched surface. The front of the cart loads soaps, disinfectants and detergents on the interior walls and ceiling, while the middle of the cart has revolving bristles to clean the surface and the end of the cart has high pressure nozzles to wisk away all the remaining dirt.
There could be a standard cart built which has modular add-on components which could have multiple tiers. The flagship model could have all the bells and whistles but sold at a higher premium than the baseline models.
Additional revenue sources could be through maintainance programs of the Sanitation Subway Carts.