Earlier this month, Congressman Seth Moulton stood before a crowd of more than 100 of the area’s top business leaders and delivered a speech loaded with terms such as “locomotive dwell time” and “stub-end terminals.”

That the Salem Democrat could give a talk more suited to a meeting of transportation engineers comes as no surprise to those who know his background (he’s a former managing director of the Texas Central Railway). But the level of interest in the intricacies of the topic…