A typical 1870's era American steam locomotive.

A typical 1870's era American steam locomotive.
Originally uploaded by Eddie from Chicago

It's hard to believe by todays standards, but early American railroad steam locomotives were actually quiete small. But just as trains they pulled became longer and heavier, the locomotives did as well.

One of the earliest standard locomotive wheel arrangements that was introduced during the mid 1800's, and had experienced a lenghty era of follow up examples for decades to come, was the 4 -4-0 type of locomotive, also refered to as the "American" type by the "Whytes system of classification".

This locomotive type, was on of the earliest standardized models. They were known for their reliability, and good tracking qualities at speed. Many were manufactured in to the early 1900's.

While the longer and heavier freight trains eventually limited their use to small branchline local switching freights or even commuter or light passenger trains, their run was a lenghty one nonetheless.
Several of these would eventually work on shortline or industrial railroads in later years. Many would be cut up for scrap during World War 2 scrap drives.

Some 4-4-0's have made it to museum preservation as well.