Conversation so far:
What was James Watt's first engine?
The first, for example, had a cylinder with a diameter of some 50 inches and an overall height of about 24 feet.
When did he make his first engine?
In 1776, the first engines were installed and working in commercial enterprises.

Question: Did any other models follow that one?
Self-contained rewrite: Besides the 1776 engine, did any other models follow?