"De train" is a French term that translates to "of the train" in English. The term is used to describe something that is related to or associated with a train. There are several synonyms that can be used for "de train" based on the context of the sentence. Some of the synonyms include "railway," "train-related," "train-bound," "train-connected," and "train-oriented." These terms can be used interchangeably to describe anything that is related to a train or the railway system. It is important to note that the usage of these terms may vary depending on the geographic location and cultural context.