I could tell you all about the trams of Havana, Cuba and how they started out as horse-drawn transportation for freight only, and how electrification of the system came fairly late, in large part because of the war with Spain. However, if you want to know more about streetcars in Havana or anywhere else in Cuba, you should really take a look at Allen Morrison's website,
The Tramways of Havana. He documents the entire history of the system, with lots of great photos and postcards.
Here's Prado Avenue with a tram and horse-drawn carriages in about 1905.
The message on the front of the card to Clara L. Gray of Minneapolis says:
Jan 13 '06
This is Prado. I tried to describe in the letter I'm sending at same time. The ocean in the distance also Morro castle. G.D.G
Here's a card showing Morro Castle.