The woman has been named by German media as 'Teresa W', who has defended the videos, in which she appears wearing her railway uniform.
Theresa W posing in the film
Speaking to German newspaper Bild, 33-year-old Theresa has insisted the videos were a 'private affair' and therefore she didn't need any permission from her employers, German railway company DB.
However, her career has since been derailed - as DB has condemned her 'alleged behaviour' and confirmed Theresa no longer works for the company as they investigate just what went down on the night train.
The videos are believed to have been filmed on regional trains in Saxony-Anhalt, in eastern Germany.
Another still from the video
They have reportedly been posted on a porn website, with titles including 'Fare Dodger Caught On Lady Ashley's Train'.
In one film, Theresa poses as a dominatrix in her uniform and punishes a male 'passenger', who has dodged his fare.
She apparently says in the video: "So, my little friend, I've caught you.
"Now I'll show you what I do with passengers who haven't paid their fares. Pull your trousers down, I want to see your naked a***!"
Theresa, from the city of Halle, then raises a whip at the fare-dodger.
Another film reportedly saw her invite a man into the driver's cab to shoot an erotic scene.
But now it's looking like her unique side gig has run out of steam, as Theresa is now being investigated by the train company, which is 'examining further steps'.
A DB train. Credit: PA
A spokeswoman for DB told the Daily Mail: "The worker in question is no longer employed by us since the start of this year.
"We do not tolerate her alleged behaviour in any way and condemn it in the strongest terms.
"It is fundamentally not allowed for DB employees to use work clothes, equipment or room space for private or commercial purposes.
"We are investigating the facts of the case and examining further steps."
Over in the UK, meanwhile, train passengers recently had a bit of a shock when 'porn sounds' were played out over a train's public address system.
Passenger Paul Brunton whipped out his phone and started filming while aboard the South Western Railway service from Wandsworth Town to Clapham Junction earlier this month.
Moaning and groaning can be heard blasting across the train, prompting the passengers aboard to start giggling - understandably.
A South Western Railway spokesperson told LADbible: "South Western Railway has a policy of blocking inappropriate material, including pornographic websites, on its onboard and station Wi-Fi services.
"We are investigating this incident to establish how this material was broadcast on our service.
"Today's incident is wholly unacceptable and we apologise to customers."
Featured Image Credit: PA