- The line is part of the now-closed Otago Central Railway which ran from Wingatui to Cromwell.
- Access to the Taieri Gorge Railway from Dunedin is over Kiwi Rail tracks with which TGR has a "running rights" agreement.
- Kiwi Rail owns the first 4 kilometres of the line from Wingatui and the Taieri Gorge Railway owns the following 60 kms of line to Middlemarch.
- The track is a single line with passing loops at North Taieri, Parera, Hindon, Pukerangi and Middlemarch. There are also service sidings at Mt Allan, Hindon, Pukerangi and Middlemarch.
- Track gauge - 1067 mm [3 ft 6 in] (New Zealand standard gauge).
- Track construction - predominantly 35 kg/m [70 lb/yd] flat bottom rail on wooden sleepers (ties) over 40 mm ballast with bolted joints (no welded rail).
- Maximum curvature - 140 m [7 chain] radius.
- Maximum gradient - 1-in-50 [2%]
- Maximum height above sea level - 254 m [833 ft]
- Minimum height above sea level - 28 m [92 ft]
- Maximum speed - 50 km/h [30 mph] (due to the small radius curves)
Number - 10
Longest - No 2 at Salisbury, 437 m [1435 ft] long
Shortest - No 7, Machine Creek, 55 m [180 ft] long
Interiors - some brick lined throughout, others lined at the portals only, depending on ground conditions.
Number - 35 between Wingatui and Middlemarch.
Largest - the Wingatui Viaduct, spanning 197.5 m [659 ft] across Mullock Gully, 47 m [154 ft] above the stream bed.
Construction - Viaducts are wrought iron, riveted lattice work construction on masonry piers.
This remains the same as the original (1880's) profile, restricting the size of vehicles using the railway. For example, Tranz Rail carriages and some freight wagons cannot use the line. Taieri Gorge Railway’s modern carriages were built specifically to fit the tunnels.
The telephone system operates via pole-mounted overhead lines between Wingatui and Middlemarch, with a link to the Dunedin Railway Station.
The original station buildings still stand at Sutton and Middlemarch, which also has a goods shed intact. Several "gangers" shelter huts of various ages can be seen along the line.
The Taieri Gorge Railway owns 6 diesel-electric locomotives, all formerly owned by NZ Railways.