A Nice Little Dinner Party - S1-E19
Continuity mistake: The train shown is pulled by four diesel locomotives, "A" unit leads with two "B" units sandwiched between a second "A" unit. When Mrs. Stevens pulls the emergency stop cord, which would not likely be on a long distance passenger train, the locomotive shown doing an emergency stop is a steam one. Not to mention that by the time of this episode steam engines were obsolete, and less likely to have been employed, especially in passenger service.
Answer: Larry had been telling Darrin what it means psychologically that Samantha gave the coat away. Larry said giving it away meant she's happy being married but if she liked the coat it means she desires to be single and carefree. So when Darrin sees the coat, he immediately thinks Samantha doesn't want to be married and the fact that she twitched it means (in his mind) she wants to be a single, carefree witch again.
Bishop73