BMT Broadway Line stations.

[braves]

What year did the new tiles & platform extensions began along the BMT Broadway Line stations & what year was the new tile & platform extensions completed.

Why was new tile put into place in the beginning.

[GP38]

What year did the new tiles & platform extensions began along the BMT Broadway Line stations & what year was the new tile & platform extensions completed.

The cement block tile was installed over the original mosaics some time around the late 60's. I don't know if that is whenthe extentions took place too, but I think it was.

Why was new tile put into place in the beginning.

Why? Because the stations were trashed, and they wanted to "renovate" them. At the time, it was thought to be a good idea to cover all the old walls with new "modern" tile. You have to remember the mindset in the 60's and 70's was "out with the old, in with the new". That was the mindset for everything, not just the subway. It went for buildings, etc too.
The new renovations with the cement block tile looked modern back then, and everyone wanted to get rid of what was then dingy filthy stations.
Of course hindsight is 20/20, and we can now think about how stupid it was to cover the old mosaics, especially now when we see how nicely they cleaned up, after they removed all the cement block tile, and once again renovated the stations, this time by restoring the mosaics that were covered for about 30 years!