Some Boston residents have criticized the slowness of the trains, especially the Green Line trolleys. Kyle Scott Clauss, the author of "The Curmudgeon's Guide to the MBTA," writes: "The C branch [of the Green Line] essentially functions as a sort of moving sidewalk leading to and from the Trader Joe's in Coolidge Corner. It was where Kenyan runner Rita Jeptoo memorably cruised past a Green Line trolley on her way to a first-place finish in the 2014 Boston Marathon."