Diesel trains in the City Loop

Normally Melbourne’s underground City Loop are only used by suburban electric trains, but occasionally diesel trains and V/Line services end up running through the tunnels – either by accident, or on purpose.

Siemens 832M arrives into Parliament on a up Cranbourne service

Railfan specials

On 1 March 1997 newly restored heritage diesel locomotive GM36 went for a trip through the City Loop with a railfan special.

Weston Langford photo

And followed it up a few weeks later on a trip to Echuca.

27 March 1999 – An ARHS & ARE combined special ran from Spencer Street to Echuca via Seymour and return via Bendigo with 1BE, 14BE, 5ABE, 2AE & Yarra. A highlight of the tour was departing Melbourne via the underground City Loop, normally electric suburban sets only.

With ‘Rail Tales’ capturing it on video through Melbourne Central station.

From Trains in Victoria Volume 2 by Rail Tales

By accident

In 2001 a V/Line train from Gippsland was accidentally sent through the City Loop.

On Friday 22nd June 2001, 8406 (0603 from Traralgon), N457+FN Set, was sent through the City Loop, after its stop at Richmond station.

M>Train were short a bloke at Metrol and a Connex employee helped out with the M>Train signalling, so he obviously assumed that 8406 was a spark, rather than a VLP train, and set it up to go through the loop. The train stopped at each of the loop stations, before arriving into Spencer Street.

I would imagine that a Y Class or something would have came along, picked up the reversed order train, took it through the reversing loop, and continued using the loco from their (N Class was No.1 end facing Traralgon [meant to be the other way], and the FN Set’s carriages ‘West’ ends would actually have been ‘East’ ends).

Again in 2008.

Was informed by a friend today who was onboard 8404 (0605 Traralgon – Southern Cross) that due to a point failure at Richmond Junction, the train, consisting of VL17, was sent through the Caulfield Loop with a pilot man, arriving into Platform 12 at Southern Cross around 08:20 (13 late).

He said that the train continued on to Flinders Street from there (not really anywhere else for it to go!)

Then again in 2017 – which thanks to the proliferation of smartphones, was captured on video.

The reason for the ‘pilot‘ guiding the train – drivers need to be qualified for the routes they travel on, and since V/Line trains don’t normally use the City Loop, drivers are not qualified to use it.

And on purpose

Metro has a special carriage fitted out to inspect the condition of the overhead wires that power trains.

In the middle of the night the laser measurement equipment is clearly visible beneath EV120

Sneaking around the suburban network without warning every few months, occasionally railfans have captured it heading through the City Loop – like I did back in 2023.

So what about the diesel exhaust?

So how do the City Loop tunnels deal with exhaust fumes from diesel trains?

Looking east along the Northern Loop tunnel from Flagstaff station

Exhaust fans and ventilation structures!

Vent structure on La Trobe Street for Flagstaff Station

Metro Trains Melbourne detail their use in a document titled “Underground Loop Operating Instructions”.


(a) Diesel Locomotives
Diesel locomotives must not be routed though the underground loop tunnels. The only exception is when the Driver is authorised to assist a disabled train or as otherwise instructed.

(b) Locomotive to Assist
If an electric train becomes disabled, it should be assisted by another electric train. If another electric train is not readily available and it is necessary for a diesel locomotive to assist, the following classes of locomotive are not to be used; ‘A’, ‘C’, ‘G’, BL & ‘N’.

(c) Locomotive Exhaust Test
When a diesel locomotive is to be used as the relief locomotive it must be held outside the tunnel entrance until the disabled train is ready to be moved. Before entering the tunnel, the Driver of the relief locomotive must conduct an exhaust test.

(d) Ventilation System
Before a diesel locomotive enters the tunnel:
1. the tunnel ventilation system must be operated in high exhaust mode,
2. the doors and windows of the disabled train must be closed, and
3. the air-conditioning system on the disabled train must be shut down.

(e) Coupling Locomotive
Both Drivers must ensure the brakes apply and release on the disabled train, before departure they must conduct a continuity test.

(f) Low Revolutions
The Driver of the relief locomotive must keep the throttle in low revs, whilst charging the air brake system on the disabled train.

(g) Ventilation to be Kept On
The Tunnel ventilation system must be kept operating for at least 30 minutes after the locomotive has left the tunnel.

And how do V/Line trains ‘accidentally’ end up in the City Loop?

The City Loop isn’t a single tunnel, but four parallel tunnels, with nine portals, scattered across five locations – and only two of them are passed by V/Line services.

Victorian Railways diagram

The first – the pair of portals for the ‘Northern Loop’ at the city end of North Melbourne station.

N class leads a H set on an up Seymour service out of North Melbourne platform 1

And the other – the pair of portals for the ‘Caulfield Loop’ at Richmond.

Missed by 'that' much - passing the Caulfield Loop portal at Richmond

Before the completion of Regional Rail Link in 2014 every single Ballarat, Bendigo and Geelong service used to stop at North Melbourne station.

VLocity VL10 picks up passengers at North Melbourne as darkness falls

But there was a special tool to prevent V/Line drivers taking a ‘wrong turn’ into the City Loop – the ‘route indicator‘ arrow on the signal at the end of the platform.

Alstom Comeng 591M gets a medium speed caution aspect at North Melbourne towards the City Loop, thanks to a track circuit failure along the line

That way if the route is incorrectly set into the City Loop, the V/Line driver can call up the signaller, and have the route changed to the correct one.

But at Richmond, the junction to the City Loop is located beyond the station platforms, where trains are moving at speed.

Tail end of VLocity VL11 and classmate at Richmond Junction, waiting for a signal towards Southern Cross

Which increases the chance of a V/Line train being caught unaware by an incorrectly set route – hence it’s mostly Traralgon trains that get accidentally sent through the City Loop.

Footnote: a new solution to ‘wrong turns’

In 2021 Metro Trains made another change to the signalling system at North Melbourne to prevent V/Line train accidentally entering the City Loop – the Train Protection & Warning System was modified so that any V/Line train trying to take the route towards the City Loop will have the emergency brakes applied.

Signal cleared for a train from North Melbourne platform 1 to enter the City Loop

A similar system but in reverse is used to prevent suburban electric trains continuing past the end of the overhead wires.

End of the overhead at Craigieburn, with only a single stabling siding originally constructed

And another footnote: not quite a diesel

In 1998 a V/Line locomotive was sent through the City Loop on another railfan special, but it wasn’t diesel powered – but an L class electric locomotive.

L1162 Parliament RTA
Rail Tourist Association photo

No exhaust fumes to worry about there!

Footnote: another inspection train

Metro also once operated inspection carriage IEV102.

'A' end of IEV102, the grill hides the air conditioner condenser unit

A 2014 run through the City Loop was captured at Flagstaff by Ian Green, and this 2021 run was snapped at Parliament by Blake Cogley.

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6 Responses to “Diesel trains in the City Loop”

  1. Andrew says:

    When the Northern Line (T9) in Sydney is closed they seem to put diesel trains through Town Hall & Wynyard quite often.

  2. Steve says:

    I always thought the ventilation structure in the Flagstaff Gardens looked like something out of the TV show ‘Lost’.

    Why would the incorrectly routed V/Line train actually stop at the City Loop stations? Just for convenience, or because it would’ve ended up behind a suburban train anyway?

    • Marcus Wong says:


      – if passengers were headed to the City Loop station anyway, stopping saves them time.


      – powering away from a station creates more exhaust than just passing through
      – confused passengers might board the train and end up at the wrong place

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