In this video, a native speaker is walking around Asakusa and describing his trip in simple sentences for learners. As he's walking, he finds an old drinking water spout, and says:
(I thought maybe he might have said 歩いて行ったら, but his own subtitles prove otherwise.) I'm unclear why he chose to say 歩いていたら, and what meaning this gives versus just 歩いたら.
I'm familiar with using verb+ていたら when the second clause is something that DIDN'T happen, like the examples below. But that doesn't apply to this sentence.
Even by thinking of 歩いていたら with "ongoing state" aspect, I'm unclear how that would translate naturally: "If you are walking, there was an old water spout." (?)
Can anyone explain?