Steam locomotive manufactures
Steam locomotive engines in the United States have nearly always been built in and for United States railroads with very few imports.
This is true because of the basic differences of markets in the United States which initially had many small markets located large distances apart; much different than Europe's much higher density markets.
Locomotives that were cheap and rugged and could go over large distances over cheaply built and maintained tracks were the early requirements. Once the manufacture of engines was established on a wide scale there was very little advantage to buying an engine somewhere else that would have to be customized anyway to fit the local requirements and track conditions.
Improvements in engine design of both European and U.S. origin could be and were incorporated by manufacturers when they could be justified in a generally very conservative and slow changing market.
Here are the names of some big locomotive builders.
• American locomotive company also know as ALCO
• Baldwin locomotive works
• Lima locomotive works
• Shay locomotive
Read about the switch from steam locomotive to diesel locomotives