The situation had unfolded as they had arrived in the town of Varney Flats enroute to Chicago, at around 1am an earthly whistle had herralded the arrival of a train, but no ordinary locomotive, the Night Train.

Unfortunately Spengler had been shackled to a ceiling post in the towns barn, as to prevent his inner demon becoming free.  Spengler didn't actually believe the Majors theory that he had a Demon crawling around inside him but he had to concede the point that something odd had happened in the town of Rotwood and when his memory returned he had burned down the towns saloon and its regulars.

So he found himself chained up when two of the bloodsuckers had entered, at first they had thought him alive, and did they get a shock.  However upon discovering him to be less than appetising they started to carve him up with their talons.
With the Major and Chewie his Sasquatch companion's help he had gotten free, just as another of the beasts entered.

The Major became embroiled in fighting the Vampires outside the barn while Chewie sucumbed to three of the monsters bite, Spengler leapt to his furry companions aid.  With a martial prowess that the living Spengler could not hope to match he flew across the barn, inserting the barrel of his rifle beneath the first creatures head and pulled the trigger, spinning around he rifle butted his next attacker and with a deft spin brought the rifle to readiness and shot the third.
As the monsters regenerated Spengler aimed and activating the Ghost Rock enhancement upon his rifle seperating each Vampires head from its body.

Egon Spengler did not realise it at the time but it was a curious thing that his fightin ability had developed so rapidly, and within the dark recess of his Soul a Manitou smiled.