Main Southern Inteceptor - Autobahn.
Rating:Updated 12th January 2001

Map of drain system with points of interest marked
Note: The map is not accurate and may contain purely fictional features in relation to above ground.

Okay, laugh if you want, but this is probably the only drain accessible to disabled people in the city. Ideal for when you fall off of waterfalls.

The MSI - Autobahn is both one of the largest and longest tunnels in the City. Created in two stages, the MSI northern tunnel was designed to replace an even older tunnel (part of still remains) that drained a large creek into the UA City River. This drain was of large capacity, but so was the creek. In 1984 flooding forced a rethink of the drain system, and it was decided to add a second large main interceptor drain along the route of a new expressway then being planned. The expressway itself traveled down the path of an old creek bed which had been covered over when the northern tunnel of the MSI was built.

With the extension of the expressway above, new tunnels were built. The southern tunnel was built when the expressway was extended and contains what was once a creek so it always has water flowing along it. (Why is it that expressways are built over creeks so much?).

Southern tunnel entrance

The southern tunnel is the larger of the two main tunnels in this drain system. It is about 20 metres wide abd 6 metres high throught it's lenth. It is probably the largest drainage tunnel in the world. At least the largest in the state.

To fully explore this drain system, it is essential that you use a car

This is a fish eye lens image of the drain, it is in fact much wider than it looks here

Check out the sections about driving in this drain

Here and Here

Midway Entrance. The Midway entrance was going to be the upstream entrance of the main southern tunnel. However, about 250 metres in from the entrance of this tunnel, the engineers had switched to a narrower tunnel construction. Still large, this narrower section was estimated to be too small to cater for 100 year floods. So the main tunnel was extended through a chamber up the old creek path for another 500 metres to intercept the creek further up. Thus the drain in fact flows underneath the creek for a little bit.

The midway entrance looks quite small, but after a short double barrel concrete drain which curves to the left, descending a ramp as it goes. The tunnel is best accessed from it's downstream end near a park and the upstream end is near a busy expressway and other roads. Just in from this entrance, the tunnel changes shape to the concrete arch shape.

Just inside the concrete sections of the middle entrance

Junction Chamber

Upstream Tunel. This section of MIS Autobahn used to be a separate drain before being connected with MIS Autobahn. Walking upstream you will come to a large chamber where light can be seen from ahead around a corner. From this chamber two rectangular tunnels curve to the right where light can be seen. Take the left one and you will come to a large side tunnel. This used to be Knightstalker's but is now the continuation of MIS Autobahn. This is another flat floored tunnel rectangular with a series of low falls in it. It is quite large and well lit from a number of grilles in it's roof, mostly at the falls. This is quite a wonderful and atmospheric section of tunnel, one of the best features around.

Turn off to upper drain section.

The tunnel at the 1st set of falls in the flat floored section of MIS Autobahn looking towards the 2nd set of falls.	The 'Arrow' falls. The third set of falls in MIS Autobahn. In 1996
Same falls in 2000

Grille in roof of tunnel

There is a lot of graffiti in this drain, some quite good, though some...... is not so good

Harpies Pit. Knightstalkers heads off east under the expressway above. The great tunnel is well lit, you don't need a flashlight to do the falls. The tunnel also has a fairly flat floor. After three of these falls the tunnel eventually turns into a large RCP. Just before the last set of falls is a large side tunnel on the left. It leads a short way to a grille room in the middle of the expressway. The small grill room is know as Harpie's Pit. The grille has a hatch in the room that is normally not locked and can be opened with a hefty push once you move the hinged bar above the grille.

Harpie's Pit Grille Room in 1996.

Above the last waterfall is an unusual section of the tunnel, flat floored but with a channel running through it. This in turn changes to a smaller RCP which is easier going as you can get up a good rhythm walking side to side in the tunnel.

This tunnel gos for quite a long way, with several short and easy slides along it's length. There are numerous manhole along the way to provide light. There's a short falls in this pipe, under a grille with a side pipe on the left. 10 minutes further on you will come to a small grille room with some fairly new brick houses on the left. This is as far as I went in this tunnel.

As this tunnel is comparatively new and unknown there is not much graffiti in it. When we visited we were surprised to find a blue hatchback car about 120 meters in the tunnel, resting on some rocks in mid-stream. It still had it's tyres on but judging from the rust and debris on it, it had been there for some time. we wondered how it got there, weather it had been driven in from that end or washed downstream from the other end. Since then five other cars have been found in the drain. Most recently they have been removed fairly soon. Most drainers will report stolen cars if they see them as they don't like people making the drains harder to explore.

The tunnel extends for quite a while along under a expressway with some side tunnels every now and then. There is a short side tunnel on the right wall that has an unusual wooden roofed section (only small). It ends in a gutter box. Eventually the main tunnel reaches it's upstream side entrance near a busy intersection. This section of tunnel is very large and is quite a pleasure to walk down.

There are occasional bits of interesting graf down this tunnel. In particular is a nice nymp picture and a picture of a UA City train.

The train

Driving in the Southern tunnel

Side tunnel 1

This section of side tunnel is an RCP, that has a branch tunnel that leads through some old tunnel that eventually gets to the main Northern tunnel.

Waterfall tunnel

About half way along the main tunnel is a side tunnel on the southern side that had quite a high waterfall in it. The ladder near the waterfall leads up to a grille in a park. That grille is movable, but only just. The ladder is often slippery.

Parking at the waterfall tunnel entrance

Explorers at the top of the falls

Looking down the falls

Trying to get the bastard grille open

Older image of the falls

Cactus Island Crawlway.

This is a bastard of a tunnel. It starts off big enough to walk through but it gets smaller until it is a little tunnel only possible to crawl through. It runs some 340 metres between the North and South main tunnels. It is a real pain to crawl along. However, about 50 metres in is a small grille room with a bastard of a grille to move. This grille opens up to the Expressway above. I have no photos of it because I could not be stuffed crawling all the way down it again.

Interchange tunnel

This tunnel is the most popular way of getting between the North and South tunnel. It is a 1.6 metre RCP tunnel that heads north from the main southern tunnel. It then reaches a small chamber and turns roughlt north west. It comes to a split where a low pipe continues west. It then turns north before reaching the main North tunnel. It is thought that this used to be a branch of the older Northern tunnel system before the larger Southern tunnel was installed.

Southern tunnel downstream exit.

This section of the drain is often knee deep in water, if not deeper. It exits into a creek which then flows downstream past a couple of other smaller drains into the UA City River.

Northern tunnel entrance

The second huge entrance of this tunnel system used to be the only entrance back when there was just this tunnel in the system. The entrance is as large as the Sothern tunnel but it gets narrower pretty quick as it slopes down to the tunnel.

Old image from 1996 showing the huge entrance of MIS Autobahn's northern tunnel

Looking down the ramp in the entrance

Looking back up the entrance ramp two explorers play in the water

Car in the northern entrance

5 explorers stand in the drain entrance

Downstream exit

The exit of the northern tunnel also exits on to a creek, a smaller one than the southern tunnel. These two creeks join up about half a kilometre away just as they reach the UA City River. This place is often the scene of flash floods, due to high water flows after storms. It is also not uncommon to see stolen cars dumped down here. This really sucks because it wreacks the enviornment and also makes it harder to explore.

Old image of the Northen tunnel downstream exit

Exit and muddy water

Exit with a stolen car washed out of it the day after a storm

The exit in a mild flood

Short section of drain upstream from the main tunnel system. Note the blue green algae

Once again well feel it is prudent to warn you that this web site is not intended to encourage you to explore drains. The exploration of drains by inexperienced people may lead to death and injury.

Do NOT enter drains. Read this warning!

		Best Viewed at
Site Map		About this site

Important warning: This site is intended for viewing pleasure, do not attempt any of these activities

©Copyright notice © This entire site is copyrighted 1997 - 2006. No image or text may be reproduced, edited, copied, stored in any off-line storage device, or placed on any another website at any time, without written permission from Panic!, web site owner.