German to English Tech/Engineering Transport / Transportation / Shipping

Hi everyone,

I'm having a little difficulty understanding the term "Rangierzug".
The context is a simulated accident between a lorry and a "Rangierzug", full sentence below:

"Für die gross angelegte Uebung wurde ein Zusammenstoss eines LKW’s mit einem Rangierzug und dem daraus resultierenden Ausfliessen einer chemischen Flüssigkeit simuliert."

I found a few things like "shifting/shunting/switch train", but with limited knowledge of trains, these terms don't mean much to me.
I wonder if it could mean a freight train, but I can't find any evidence of this online...

Thanks for your help!