The Lorton and Occoquan Railroad, owned by the Department of Corrections and operated by its Engineering Division, served the Lorton Reformatory (original a penal colony) between 1915 and 1977. It replaced the original cable car/pulley system in place (since 1911) to haul cars up the grueling 7% grade from the banks of the Occoquan River; during its life, the railroad hauled raw materials and inmates into the facility, and hauled finished goods out.

As the facility was being built, a ferry-barge service was instituted that hauled supplies and inmates from Washington along the Occoquan River to the site of Occoquan proper, where they were loaded onto narrow-gauge flatcars and towed by cable/stationary steam engine out of the valley and into the facility to the east. In 1915, consideration was given to electrify the line, so work began (primarily by inmates) on widening the line to standard gauge and extending the line beyond the valley and deep into the facility where it would serve the workhouse, an on-site quarry, and the reformatory building itself. Ultimately, at 4 miles long, the line would connect to the Richmond, Fredericksburg & Potomac Railroad on the east side of the facility via a wye.

While work continued to build the line, it was further considered that an electric line couldn't sufficiently handle the 7% grade coming out of the river valley, so the decision was made to acquire a steam engine. Reformatory officials consulted with the American Locomotive Company (ALCO) as to the proper type of steam locomotive to handle the grades and roughness (being built by inmates) of the reformatory's track, and a custom-built 2-6-2T tank-style steam locomotive was decided upon, numbered #1.

The line was completed to the reformatory building by 1920, and eventually reached the RF&P near Pohick by 1922. The line was not sturdy by any means; indeed, the reformatory's superintendent even walked across the rickety wooden bridge over the Giles Run instead of riding on the locomotive during his inspection run.

Coal, building materials, and inmates arrived by barge from Washington DC on the west end of the railroad, while waste/sewage arrived via the RF&P on the east end of the railroad (destined for dumping sites along the L&O right-of-way, and continued until after WWII), along with food and fertilizer. The railroad exported finished bricks produced by internal work programs. Locomotive #1 could only muster enough traction to haul one boxcar at a time up the 7% grade out of the Occoquan valley; on the other end, a 4% grade up from the RF&P connection limited the #1 to only two boxcars at a time. Within the facility, the railroad carried foodstuffs, laundry and scrap between buildings. And the entire operation ran with just one civilian engineer and one civilian mechanic, while inmates were "hired" to do the rest. In order to discourage the railroad being used as a means of escape by the inmates, numerous derails were placed along the line that had to be operated by hand every time a train approached; a train was always inspected at a guarded gate at each end of the railroad as well.

Locomotive #1 worked faithfully from 1919 to 1937, when it was scrapped and replaced by a Porter 0-6-0, previously used at the Washington D.C. Water Works. This locomotive tarried on until 1947, when diesels were brought on the property: a 45-ton Cooper-Bessemer engine, a 65-ton Cummings engine, and a 45-ton GE switcher. Rolling stock was acquired as surplus from other government entities.

In 1977, the decision was made to decommission the railroad, owing to the value and convenience of shipping over roadways. The equipment from the line was sold in 1980. Most of it was scrapped, except for the diesel locomotives, which now find home in Alabama on a tourist railroad.

Today, the Lorton and Occoquan Railroad is primarily paved over, but some portions remain and are visible.