2 Baon Wartowniczy is not a street or place;it is a service brigade your father was in and located in Lwow.
II Baon Wartowniczy took a prominent part in the defence of Lwow in the first World War and is mentioned in a book called BOJ O Lwow. (Battle of Lwow- Defence of Lwow), together with Baon I and III.
There does not seem to be any mention of location of its' barracks.Just action - all in Polish.
I looked at Russian lists and cannot see any reference to Stefanko /Stefanko or Jachimiuk-Jachimiak, with this spelling.
Best is to refer to Karta in Warsaw giving more detail and the chance they might have something.
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