Running The Narrows - Part II. The constant hum of rush hour traffic in downtown Cumberland begins to fade as the ears become aware of an almost explosive, staccato barking sound approaching from the south. Within seconds, the volume becomes so loud that the traffic noise disappears. Cars weave and brake as drivers struggle to find the source of the approaching tempest. And then out of the morning mist, here she comes, running along the concrete viaduct, her deafening exhaust now echoing off the canyon walls. For just a few seconds until she passes, she's the focus of everyone within a quarter mile. Yes, even though she's been plying the rails between Cumberland and Frostburg for many years now, the Western Maryland 734 still stops traffic and creates quite the spectacle, every time she leaves the yard. Experience this scene just once, and you'll fully understand how this locomotive came to be called "Mountain Thunder".