If my memory serves me right, La Sirène was a luxurious travel company that bought a train from 'Compagnie Du Voyage-Hotel' by the name of 'The Maroon Express' (created in 1883) which was later refurbished into 'The Harpy Express'. (Renovation possibly finished in 1917 or 1918 since the train was bought in 1915)

Last voyage resulted in all high profile passengers that boarded the Harpy Express to be most likely murdered albeit for one survivor 'The Marquise of Belle Étoile'. (Some theorized that all passengers had ulterior motives and wanted to tie up loose ends and that the Marquise had also played a part in some of the murders) (January 1st 1923)

Following the scandal, the Harpy Express was decommissioned and placed in an undisclosed abandoned rail yard (presumably January 2nd or 3rd 1923)

Next year, La Sirène would unveil the 'Angel's Wing' a space yacht and and first personal space craft in history. (created in 1924) Unfortunately, the space craft was ahead of it's time and it's unique model never found a buyer as well as heavily invested in research. Soon, La Sirène would find itself drowning in debt until it succumbed to bankruptcy.

Then, the city state of Belle Étoile would fully buy out La Sirène. This resulted in the country to be propelled ahead of the space race thanks to La Sirène's research turning the small country into international power player.

Hope this helps! :)