When Twinkleshine boarded the train in Canterlot, she headed towards the first car. It was well known that the soot from the locomotive didn’t fall that quickly, and to a pony with a white coat, such a consideration was important. The ride was smoother, too—when she’d asked the conductor why, he’d told her it was because of the slack action. She didn’t know what that was, but took his word for it.