In 1830, Welch joined engineers of Canvass White in Trenton, New Jersey on the construction of the Delaware and Raritan Canal.

In 1844, Welch traveled to England and supervised the construction of an order of guns for the United States Navy.

In 1863, Welch led the efforts on installation of a block signaling system on the Camden and Amboy Railroad between Philadelphia and New Brunswick.

[2] On October 25, 1834, Welch married Mary Hannah Seabrook in Lambertville, New Jersey.

On September 25, 1882, Welch died in his home on 21 York St, Lambertville, New Jersey.