Helensburgh NSW 2508
Eight Railway Tunnels near Helensburgh — Full Guide
Last updated 6 August 2026
When the original Illawarra railway was built in the late 1880s, engineers punched eight tunnels through the sandstone escarpment between Waterfall and Clifton. The line opened in stages from 1888, linking Sydney to the southern coalfields and dairy country — and putting Helensburgh on the map.
Steep grades, single track, and smoky steam locomotives made several tunnels infamous. Between 1915 and 1920 the line was deviated around Stanwell Park onto an easier alignment. Most of the old tunnels were abandoned; one still carries today’s South Coast trains. This page is the hub guide — each tunnel has its own detailed entry on Helensburgh.com.au.
Quick facts
Why the line was so difficult
Gangers worked south from Waterfall through Cawley, Camp Creek (Helensburgh), Lilyvale, Otford, and Stanwell Park from 1884. The escarpment demanded tunnels, sharp curves, and grades as steep as 1 in 40 in places. Once open, heavy coal and passenger trains struggled uphill toward Waterfall in heat and smoke — engines stalled, crews suffered, and passengers endured suffocating conditions in the longer bores.
Tablet working and ventilation shafts helped temporarily, but traffic growth made the old alignment unsustainable. The Stanwell Park deviation (completed 1920) bypassed the worst grades and several tunnels. Much of Lawrence Hargrave Drive today follows the old rail formation — see Stanwell Park Overbridge for how road and rail once intertwined.
Original Illawarra line
The eight tunnels
Waterfall to Clifton — numbered south to north as built in the 1880s. Tap a tunnel for the full guide.
-
1
Waterfall tunnel
221 m
Rail ended: duplication works
Daylighted -
2
381 m
Rail ended: ~1915
Abandoned -
3
80 m
Rail ended: 30 May 1915
Landcare reserve -
4
Metropolitan / Glow Worm tunnel
624 m
Rail ended: 30 May 1915
Landcare; etiquette Read guide → -
5
80 m
Rail ended: 20 May 1915
Private land -
6
322 m
Rail ended: 30 May 1915
Colliery access -
7
~1,550 m
Rail ended: 10 Oct 1920
Abandoned — unsafe -
8
Clifton (Bald Hill) tunnel
~1,000 m
Still carries South Coast trains
In use today
Access warning — August 2026
Most disused tunnels are not formal tourist attractions. The glow worm tunnel at Helensburgh Station Reserve is Landcare-managed — the 2018 fence was later removed after colony recovery; still follow glow-worm etiquette (see the Metropolitan Tunnel guide). Lilyvale tunnels cross private land and active colliery infrastructure. The Otford Tunnel is dark, flooded in places, and has no mobile coverage. Do not enter private or colliery-fenced land.
After the railways left
Abandoned tunnels found second lives. Several became mushroom farms — including the Otford and Lilyvale bores. The Metropolitan Tunnel held water for the colliery and later became famous for its glow worm colony, drawing crowds until overcrowding and vandalism forced fencing and managed closures from 2018 — later eased after the colony recovered (fence removed by 2025).
During World War II, coastal defence plans called for destroying key tunnels. The army partially collapsed the Otford Tunnel near its southern portal in 1942. The Clifton tunnel survived and still carries NSW TrainLink services on the South Coast line.
For a fatal accident in one of these tunnels, see Death in the Railway Tunnel — Ian Piggott’s analysis of conflicting 1895 newspaper reports about miner Robert Hails.
Related pages
Sources: State Records NSW; Helensburgh and District Landcare Group; John Oakes, Sydney’s Forgotten Illawarra Railways; individual tunnel pages on Helensburgh.com.au.