I’m not sure what this is, never seen it before. But I’ve been color correcting my Waffen SS photos that I will be posting on the site soon. These have never before been published. Check out this pic. What kind of train/rail car is this? Notice the big machine gun in the front car.
Ha! German War-Roller Coaster! 
…Well…It looks the the gentlmen are wearing M36 tunics, so it’s most likely very early war.
It looks like the German War-Roller Coaster was used in the invasion of Poland and in the early 1940’s. After that they probably took it out of the service for the Waffen-SS. Wow Wolfgang Von Gottberg suprised you knew that. It seems you know alot about the Waffen-SS.
They are Wehrmacht EMs wearing M36 Tunics. You can tell this by the bottle-green collar on the tunic. They are also wearing M35 steel helmets with the right decal (tri colors) attached.
There for, these could even be German soldiers in Czechoslovakia!
I’m guessing it could originally been used for civilians, just because of the unbrella in the first car.
Trying to dig up more info…
(Oh yeah, the Germans invaded Poland in very late 1939)
Tri-color decal on the right side of the helmet was canceled in march 1940 but I saw many fotos with Germans wearing helmets with such decals in the late 1940. So this foto may be taken till the end of 1940. So as you know it may be in Chez, Denmark, Norway, Poland (invasion 1 september 1939) or even France (invasion May 1940) At that time decal was already canceled but still often could be met in front line troops)
According to a book titled Steel Rails to Victory, the photograph of the motorized rail cars was taken May 22, 1940 during the invasion of Belgium.