The railing behind the palace dates from Quarenghi's time, but the terrace had to be rebuilt and reset. This area of the place had problems with an underground stream and it caused cracks in the foundations and vaults of the semi-circular hall during construction. You can see the railing still has lots of damage from WWII that was not repaired in the mid 90's. I have great pictures of the front railings and light fixtures from the 20's and you can see that they were painted light blue. The pictures show the guard station up close as well. Alexandra's balcony was painted the same color. The railings of the balcony can we seen at the Hermitage and at the Belvedere Palace, they seen to have been 'stock' from the ironworks of the time.
I have never seen pictures of the balcony after the war. I don't know if the Germans stripped if for scrap and sent it off to Germany, or it was so badly damaged that there was no way to save it after the war or (this is the most likely) the balcony was pulled down on purpose after the war to eliminate something that was too clsoely associated with Alexandra. We know that many of the rooms - including the Maple Room survived the war only to be destroyed by the Soviets.
Throughout the palace - inside and out - there were many remains of heating systems, window mechanisms, electricity, when I was there in the early 90's. A few years later most of this had been swept away. I hope documenting photographs were taken before this destruction took place. As I have send before in the 90's the museum authorities did not want to restore the rooms of Nicholas and Alexandra and there were plans to destroy the New Study and Nicholas's Reception room. The intent was to restore the palace to the time of Nicholas I. Thank God - and I mean THANK GOD - the museum authorities did not have the money to do this. There was a great dislike of Nicholas and Alexandra then - even hostility towards them. Interest in them was considered a foreign 'obsession' and a sign of lack of culture in Tsarskoe Selo. Certainly this has changed but the damage done deliberately and through neglect is there.
As I have written elsewhere what was done to the roof on the Imperial Wing when it was replaced was barbaric and completely unnecessary. The money was given for a proper replacement and what was done was a hack job that destroyed evidence from all periods of the palace dating back to the original construction.