Austrian rail operator OBB said that it had filed complaints against two people for allegedly using train loudspeakers to play Hitler speeches and Nazi slogans.
The two suspects were reported to Austrian police late on Sunday. Law enforcement had identified the pair by analyzing footage from surveillance cameras.
The OBB confirmed that the two suspects were "not OBB employees."
The incident included what appeared to be excerpts from the Adolf Hitler's speeches as well as the Nazi salutes "Sieg Heil" and "Heil Hitler."
Austria was annexed by Nazi Germany in 1938 and today, it has some of the world's strictest laws against Holocaust denial and pro-Nazi activities.
What else did OBB say about the incident?
OBB spokesman Bernhard Rieder said the suspects obtained a generic key to gain access to the train's intercom station and then played the material off of a mobile phone.
"It is a standard key used throughout Europe, of which there are probably several tens of thousands," Rieder told Austrian daily Der Standard. "An external hacker attack can be ruled out."
"Everything was played very loudly. It was really unpleasant and disturbing," he said.
The loudspeakers also played a selection of bloopers by Austrian actor Chris Lohner before moving on to excerpts from Hitler speeches.
The incident comes after two trains were manipulated last week to play a mix of children's songs and old announcements last week.
All three incidents occurred between the eastern Austrian city of St Polten and Vienna.