Metropolitan Tunnel (Glow Worm Tunnel)

About the tunnel

Helensburgh, NSW, Australia is home to a remarkable sequence of historic railway tunnels, with the Metropolitan Tunnel — locally known as the Glow Worm Tunnel — being the most famous.

The Metropolitan Tunnel is the 4th tunnel on the original Illawarra Line. It is a 624-metre single-track tunnel on a 1 in 55 grade (falling south), nestled between the Helensburgh Tunnel (No. 3) and the Metropolitan Colliery.

• Opened: 3 October 1888 (some sources cite 1 January 1889)
• Closed as a railway tunnel: 30 May 1915 (line deviated)
• Length: 624 metres
• Reserve name: Helensburgh Station Reserve (gazetted December 2018)
• Managed by: Helensburgh and District Landcare Group Inc (Crown land managers)

Like the Otford Tunnel, the Metropolitan Tunnel suffered from soot, smoke and steam build-up — treacherous for crews and passengers. After closure, the colliery used the tunnel as a water reservoir; a concrete plug was installed at the southern end in 1928.

Current status (2026)

The tunnel's popularity led to serious pressure on the glow worm colony and heritage fabric of the site:

• June 2018: A fence and gate were installed after reports of heritage vandalism and glow worm disturbance.
• December 2018: The NSW Government gazetted the Helensburgh Station Reserve, appointing Landcare as Crown land managers.
• January 2019: Landcare closed access for four weeks during glow worm breeding season to allow recovery.
• 2020: Further closure due to flooding and continued conservation needs. The dedicated glow worm tunnel website is no longer maintained.

The northern portal area, including remnants of the original Helensburgh Railway Station platform, may still be viewed from outside the fenced area in some circumstances — but entering the tunnel itself requires Landcare permission when access is granted.

Looking for a glow worm experience elsewhere in NSW? The Glow Worm Tunnel walking track in Wollemi National Park (near Lithgow) is a different tunnel — do not confuse the two.

Ian's story — discovering the tunnel

Every day I'd commute to Helensburgh Railway Station and catch the train to school at Heathcote. One morning as I was riding my bike to the station, my friend pointed into the thickets of lush green overgrowth and said "In there is an old train tunnel." I didn't think much about it at the time, but the curiosity never left me.

On occasions when leaving Helensburgh Station heading to Sydney, the bush around the 1st Helensburgh Tunnel can thin out due to fire or drought, and you can clearly see the northern portal.

After high school I used to walk past the area in Tunnel Road every Friday evening. I would attempt to peer into where the Metropolitan Tunnel is, but it was either too dark, or very overgrown and full of rubbish and water.

Excavation and rediscovery (1995–2002)

In years past the whole tunnel was virtually full of water, giving rise to rumours of an abandoned steam train submerged inside. When the tunnel was drained in early 1995, that rumour was put to rest — no steam train was found.

Metropolitan Colliery cleared rubbish from the northern cutting. Rail enthusiasts, local historians and colliery contractors then uncovered brickwork of significant historical importance — part of the original Helensburgh 1st Railway Station platform, still in situ. A good length of platform was unearthed and can still be visited at the reserve today.

Thanks to Helensburgh Landcare, much of the site has been restored. In March 2002, rail and wooden sleepers donated by Metropolitan Colliery were laid to dramatic effect. Just metres from the northern portal stands the old railway station platform of the 1st Helensburgh Railway Station.

The southern end remains blocked by a concrete wall constructed by Metropolitan Colliery — the tunnel is leased for mining water storage and dust management.

Glow worms

Not being used for mushroom production (as some other local tunnels were) allowed the Metropolitan Tunnel to host one of the largest glow worm colonies in NSW. The bioluminescent larvae of fungus gnats create the famous blue-green glow — but the colony is extremely fragile.

Torches, camera flashes, insect repellent, smoke, noise and large groups all harm glow worms. This is a key reason access has been restricted.

Tunnel etiquette (when access is permitted — Merilyn House):

1. Keep noise to a minimum — for the glow worms and neighbours.
2. Apply insect repellent before entering — repellent inside the tunnel can kill glow worms.
3. No smoking — smoke kills glow worms.
4. Do not use camera flash. Use night mode for photography.
5. Point torches at the ground, not the roof.
6. Keep group sizes small (4–8 people).
7. Take out what you bring in.
8. Respect neighbours — they live beside the tunnel every night.

Heritage and the station sign

The whole area is environmentally and heritage listed. The original Helensburgh and Metropolitan Tunnels, and remnants of the former station platform, are vested in Crown land and managed as the Helensburgh Station Reserve.

In 2012, the original Helensburgh Railway Station sign was vandalised — several original letters were forcibly removed. The sign was removed for safe keeping. If anyone knows the whereabouts of those letters, please contact us — you can remain completely anonymous; we would simply like to see them returned.

Video

Location

The reserve is near the intersection of Vera Street and Tunnel Road, Helensburgh NSW 2508. The current Helensburgh railway station is on the South Coast line — approximately 45 km south of Sydney Central.

Related pages

• Helensburgh Railway Station Reserve
• Helensburgh Tunnel (No. 3)
• Railway Tunnels near Helensburgh
• Death in the Railway Tunnel — Robert Hails, 1895
• Otford Tunnel
• Glow Worm Tunnel closure notice (2020)
• Helensburgh town guide