A rider on tonight's 6:15 p.m. train on the Kingston/Plymouth Line out of South Station e-mails this report:

Ever wonder what a "switch problem" is? In this case it means that the train stopped just south of North Quincy. Then the train proceeded to back up . . . all the way to the gas tank. The conductor said that we were backing up because we were on the wrong track. I half expected Bugs Bunny to pop out of a hole and say, "Looks like I made a wrong turn at Albuquerque!"