The site of the Great Zig Zag was declared a public reserve in March 1881; one of the first in NSW. From the time of construction 1866-9 it was a popular tourist destination as well as an important commercial utility. The first Bottom Points station was opened in April 1878 to cater for visitors. It has remained a popular tourist attraction, with its fine sandstone escarpments, exotic rock formations and mountain views.

The principal constructions on the reserve are the three sandstone viaducts, the two 'wings' at Top and Bottom Points, and one of the two tunnels. 

Clarence Tunnel c. 500m (1617') lies outside the Reserve, built by William Watkins. It is straight apart from a curve at the Clarence end. It is the highest railway tunnel in Australia. It was used a a dump for gas bombs in WWII.

No. 1 Viaduct, 7 arches, 2 x 4.57m (15'), 5 x 9.14m (30'), on a 201.2m (10 chains) curve, with a maximum height of 14m., (46'), c. 82m (270' - 90 yards) long.
No. 2 Viaduct, 9 arches of 9.14m (30') each on a straight alignment, with a maximum height of 23.16m. (76'), 99m. (330' - 110 yards) long.
No. 3 Viaduct, 8 arches of 9.14m (30') each, on a 140m (7 chain) curve, 91m. (300' - 100 yards) long.
No. 1 Tunnel, length 68.6m (225' - 75 yards) on a 161m. (8 chain) curve, with sandstone lining.
'Half Viaduct', at Top Points. Originally top Point Wing Viaduct, (single 30' arch). In 1895 the inner side was taken down and the area filled in.

All the viaducts and No. 1 Tunnel were built by Patrick Higgins.
Further information about sandstone viaducts in the area.

The Bottom Points Signal Box between Bottom Points station and the depot, was moved from the further side of the main line and rebuilt in 1993. Vibration by heavy coal trains had caused the Signal Box to tilt towards the main line and it was in danger of collapse. It was originally built in 1910 next to the main line for the 10 tunnel deviation. There is anecdotal evidence of it having been moved from Oakey Park to Zig Zag. It is in the style of the earliest NSW signal boxes, surviving examples date from 1885.

The Top Points Signal Box was built in 1998 in the style of NSW signal boxes to replace one that burnt down in the December 1997 fire.

The Zig Zag Dam. Built in 1868, it is a sandstone buttress dam and holds over 1,000,000 litres, 4m (12') high, 15m (50') wide. It is one of the oldest dams in NSW, if not Australia. Parramatta dam, a sandstone arched dam, was built in 1856.
In the early 1970s the dam was partially excavated to dump valve level by volunteers. In March 2003, towards the end of the drought, the dam was fully drained and 100s of tons of silt removed, together with other debris dating back to the time of its construction. It is described on the NSW State Heritage Register as being of high significance.

There are a number of fine sandstone retaining walls and culverts (2' - 4') on the Reserve.

Cooerwull Railway Footbridge, 1941, built to provide access between Cooerwull railway station (removed 1974)  in Lithgow and the Small Arms Factory. It is the last A frame timber bridge in the State, built to the simplest design with local materials, These modest footbridges were seen in many places in the State, usually where the line was in a small cutting to provide a higher foundation on each side of the line.
It was replaced by a modern steel bridge some years ago. The bridge was moved to Top Points in 2002.

The Reserve is listed on the Register of the National Estate, the NSW State Heritage Register and the Register of the National Trust. The Reserve is administered by the Zig Zag Trust, whose board of Trustees is the Board of the Zig Zag Railway.

The Reserve is funded from fees received from the Zig Zag Railway Co-op Ltd.