Pioneer is the first railroad locomotive to operate in Chicago, Illinois.

It was built in 1837 by Baldwin Locomotive Works for the Utica and Schenectady Railroad (U&S) in New York, then purchased used by William B. Ogden for the Galena and Chicago Union Railroad (G&CU, the oldest predecessor of Chicago and North Western Railway).

The locomotive was built by Baldwin in 1837 for the U&S which gave it the name Alert.

It worked almost a decade before being sold in 1848 to the Galena and Chicago Union Railroad.

The G&CU renamed it Pioneer and used it in the construction of the G&CU until 1850, when it was loaned to the Chicago, Burlington and Quincy Railroad for work laying the first track in Chicago that summer.