I have never heard of this expression before but I'm guess it refers to the fact that nowadays trains use digital signals instead and as a result they don't have caboose/brake van anymore. So (without context), it probably means that the person who said it believed that caboose is important and safer than digital signals? Or the trains will be safer to have a live human being watch out for it ?
Definition of baby. plural. babies. 1a (1) : an extremely young child; especially : infant (2) : an extremely young animalb : the youngest of a group He is the baby of the family.
term infant. Etymology: L, terminus, limit. any neonate, regardless of birth weight, born after the end of the thirty-seventh and before the beginning of the forty-third week of gestation. Infants delivered at term usually measure from 48 to 53 cm from head to heel and weigh between 2700 and 4000 g.ny neonate, regardless of birth weight, born after the end of the thirty-seventh and before the beginning of the forty-third week of gestation. Infants delivered at term usually measure from 48 to 53 cm from head to heel and weigh between 2700 and 4000 g.