Hi, don't know about Langrig, though familar name, but Earlston Avenue, I remember well. I agree that 911 couldn't be there but I'm sure there was a 91. Earlston Avenue, as the other contributor said, ran from Royston Road to Royston Hill. Both ends had shops, with a couple more in between. It also passed Rhymer Street (this whole area is Townhead). I lived there from birth to age 16 yrs, before it was demolished as part of the redevelopment and the new M8 motorway construction. We moved to Dennistoun just a mile away. The site of our old house is still there, bare and grassed over with some new housing on the remainder of the site.
Behind the houses on the left side of Earston Avenue (heading towards Royston Road) was the canal where we all played as kids and often got into trouble. Several fatal accidents happened there. The canal ran across (rather under it) Royston Hill where it passed a large area of factory type units and garages. A few years ago (about 2004-5) I was contacted by an old friend who lived in Earston Avenue, something like No. 1 or 3 - the Royston Hill end of the avenue, and played professional football for a Scottish league team for many years.
The shops I remember in Earslton Avenue were Traynors (or Trainers) which was a tobaccoonist/newsagent, and next to it was Ellens(or Helen's) which was provisions, groceries etc. There were just past Rhymer Street, the corner of which had a pub (name escapes me). Were you looking for someone in particular at "911"? I had a lot of friends in the area, and was a member of the 78 and 191 Boys Brigades at Townhead Parish Church (my uncle was Church Warden) (and now a monument) and Martys Church. I went to St Rollox School (later called Royston Road Primary) then Onslow for two years before changing to the then new Smithycroft. From Rhymer Street, we'd walk down Royston Hill to Castle Street to catch the 38 bus along Alexandra Parade to get to school.