Step 1: Identify the sentence → “The members of his family are coming in this train and I am sure that it will be a memorable trip for all of them.”
Step 2: Focus on the phrase needing correction → The expression “coming in this train” is not idiomatic in English. The issue lies in the use of the preposition “in.”
Step 3: Recall the rule for transportation prepositions → In English, we say “by train,” “by bus,” “by car,” etc., when referring to a mode of travel. The preposition “in” is not correct in this context.
Step 4: Apply the correction → The correct sentence should be: “The members of his family are coming by this train and I am sure that it will be a memorable trip for all of them.”
Step 5: Apply the formatting instruction → Since the answer must be concise without spaces, the correct response is given as a single word.
FinalAnswer:by