1. Green Line train: "Take the next cah to Nawth Station; get off at Haymahket."

Waiting for the Leech-meah cah at Pahk Street:

2. An auto. By itself, not surprising, given the pronunciation, except that it leads to a joke that only a Boston kid would get, as Christine Leccese explains: "When we were kids (in Burlington), we played on the street a lot. When a car would come, someone would scream 'Cah!' and we'd all run onto the grass. Well, when two cars would come 'cah cah' would send us all into hysterics (cahcah=caca)!"