Vehicle / Weapon identification request

I recently acquired some photos from the ETO and could use some help identifying the vehicles/weapons below. The unit is a 155mm towed howitzer unit. The top two pics I'm pretty sure are German. For the bottom two I know they used "M5 tractors" as the prime mover; are the bottom photos M5s?

 

There were two guns that made up the German K-5 RR battery that shelled the Anzio Beachhead. "Robert" and "Leopold" were the names the Germans gave the two guns. Together, they composed "Anzio Annie." On June 7, 1944, the 168th Infantry Regiment of the 34th Division captured the guns. Leopold was the less damaged and was sent aboard the liberty ship Robert R. Livingston to Aberdeen Proving Ground, Maryland.

 

Very nice pictures,

First one's interesting.
Immediate thought is some sort of StuG or StuH, very tricky to choose an exact type from that angle. (Sorry, possibly pre-assuming nerdy knowledge there - Stug/Stuh = Sturmgeschutze/Sturmhaubitze - assault guns).
(But, that barrel support (if that's what it is) is rather more substantial than usually seen on those types. Interesting scalloped effect to the bottom of the schurzen too, though that might be more a creation of using what looks like two front, or a front and rear, right next to each other.
Hmmmm. Bit more staring required there to be 100% certain of what's what, any more of the superstructure visible behind those plates in the original scan?)

#3 Is indeed an M5 HST (High Speed Tractor)
#4 Ditto.

~A

 

Interesting to see the pics of that High-Speed Tractor ; fits in well with another recent thread which also has some links...

http://www.ww2f.com/modelling/48478-m4-high-speed-allis-chalmers-tractor.html

 

Hard to imagine an unidentified piece of armor being on the forum for more than 24hrs and Adam not having a bead on it.....He must have a fever.

 

The railway gun is of French orgin. Here's the history on that photo:

File:274mm45 railroad gun captured Apr1945.jpeg - Wikimedia Commons


The assault gun in the first picture is almost certainly an StuG IV. The drive sproket is a Pz IV type not a Pz III model.

 

Thank you all for your replies, I truly appreciate and admire your expertise.

The photos are from a soldier in B Battery, 203rd FA, that fought the Normandy, Northern France, Rhineland, Ardennes, and Central Europe campaigns, primarily with the 119th FA Group/XIX Corps.