3801 Limited was formed in 1985 to maintain and operate locomotive 3801 and now, as well, operates heritage diesel locomotives and heritage rollingstock.

3801 Limited runs day tours and charters to the Blue Mountains, the Hunter area and the Southern Highlands as well as regular tours to rural areas. In addition, the company runs the Cockatoo Run on Wednesdays and Sundays on the Unanderra to Moss Vale line.