Smoking room and Smoking car

Smoking room noun - Room in a hotel or club set apart for smokers.

Smoking car and smoking room are semantically related In some cases you can use "Smoking car" instead a noun phrase "Smoking room".

Smoking car noun - A passenger car for passengers who wish to smoke.

Smoking room and smoking car are semantically related in compartment for smokers topic. You can use "Smoking room" instead a noun phrase "Smoking car".