Dear teachers,

Please tell me if the following sentences are, what is called, "participial construction" or not. Or are these sentences nothing related to "participial construction"? In other words, can the part formed with "When + ~ing" (e.g., When calling, When discussing, When gathering) or "When + past participle" (e.g., When asked) has the same subject as the one in the main clause? In my understanding, a participial construction is established, in principle, only when the subject of the adverb clause and the subject of the main clause are the same though...

Example 1) When calling for roadside service, please have the following information readily available.

Example 2) When discussing our sales performance, he pulls no punches.

Example 3) When gathering speed, this power along with power from a diesel engine is used to operate the motors.

Example 4) When asked about kicking the habit, 60 percent said they could quit if they wanted to.

Someone, please help me explain.
Your examples are of participial construction and rightly bear the same subject as the main clause. However, participial constructions also exist outside that relationship.

With the wind blowing abeam, we quickly tacked to the inlet.-- Here, the participal clause is the object of a preposition.
Thank you for your information, Mister MicawberEmotion: embarrassed
However, I am still a bit confused. If these are of participal construction,
could you please help me identify what the subjects for these four examples
so that I may be able to gain more understanding for what you mean?

Thank you again for your great help in advance!