Collection of samples from MBTA trains and stations. Collection of samples from MBTA trains and stations. (A) Microbial community samples were collected from the Massachusetts Bay transit system in the metropolitan area of Boston, MA. Train samples were collected from 6 train car surfaces across 3 locations along 3 train routes; station samples were collected from 5 stations. Horiz, horizontal; Vertic, vertical. (B and C) Diagram of the surfaces sampled within train cars (B) and stations (C). Sampled surfaces specifically included seats and seat backs, horizontal and vertical poles, hanging grips, and walls within train cars, as well as the screens and walls of touchscreen machines within stations. Tiffany Hsu et al. mSystems 2016; doi:10.1128/mSystems.00018-16