Side-by-side Tunnels

Ken, the Chunnel has three bores. See

Sure ... there are several possibilities. When two different railroads both follow the same route (not uncommon), and come up against the same obstruction, they both have to do pretty much the same thing. One such example: For many miles across Montana the MILW and NP ran side by side, often no more than a couple hundred feet apart. They had paired side-by-side tunnels as you decribe. Some are quite short ... from a ways back you can see through both at the same time.

I suppose there might also be other places where the material to be tunneled through is more conducive to two smaller bores than one big one. Also, if one single track tunnel already existed, and then a second was needed, digging a new bore would allow the existing one to continue in service during the construction.

Several under-river tunnels are single trackes and side-by-side for similar reasons. Some are made on dry land as tubes, then sunk in the river. Others are dug like conventional tunnels. The side-by-side CN tunnels between Port Huron, MI and Sarnia, ONT were both dug. The old one got too small for modern equipment, so they dug a new larger tunnel alongside. For a short period after the new tunnel was completed both were useable, though the old tunnel is now abandoned for RR traffic (it's still used as as communications cableway).

So, not common, but such arrangements do/did exist.

Dan Mitchell ============

"> > I was wondering how many single track tunnels exist side-by-side in the "> > prototypical world. The only image I can mentally bring up is the scene at "> > the "> > end of the movie "Defending Your Life" that shows all the trains taking "> > people "> > from the afterlife to their next lives going through many side-by-side "> > tunnels. "> >

"> > Does such a multiple tunnel arrangement exist in the real world? "> >

"> > I ask because my layout has five parallel tracks going under a mountain. "> > I'm "> > thinking of using five side-by-side single tunnels. It doesn't look as bad "> > as "> > it sounds. "> >

"> > -- "> > Ken Rice -=:=- kennrice (AT) erols (DOT) com "> "> Ken, the Chunnel has three bores. See ">

"> "> -- "> 73 de KT0T "> Bob Schwartz "> Modeling Waseca, MN in the '50s "> "> ">

\/ Robert Heller ||InterNet: snipped-for-privacy@cs.umass.edu

"Daniel A. Mitchell" wrote in news:qCNde.1209$ snipped-for-privacy@news.itd.umich.edu:

I suspect we will see more and more of these parallel bores in the future (not necessarily limited to RR tunnels) with the advent of sophisticated tunnel boring machines such as were used for the Chunnel and parts of Boston's "Big Dig". They always cut a round hole

They've used "baby" versions of these in our community lately to install large storm drains. (Although it's hard to call a machine that bores a 10-foot diameter hole a baby!). This sure beats digging a massive trench down the middle of a street!

The current Alp Transit tunnels in Switzerland are being bored as two parallel bores. The Gotthard tunnel will be cross connected in the middle. Gotthard bore should be the longest in the world when finished. Project is massive....

Yeah, especially on the Big Dig. They cut a big ol' round hole right in the rear ends of the Massachusetts taxpayers.

Tepid Pilot

snipped-for-privacy@aol.com (Tepid Pilot) wrote in news:4277d70a.1433023 @news.intcomm.net:

Since I live far from Beantown, I haven't kept up with all the news on that project. I have heard that it was a bit controversial. Wasn't there something about leaks and flooding?

On Tue, 3 May 2005 15:08:02 UTC, snipped-for-privacy@email.ads (Ken Rice) wrote: 2000

On the Espee there is such an instance in the Rocklin Colfax area. There are two bores right next to each other coming out of San Francisco. At Norden in the Sierras there are two bores which are not parallel or adjacent but they carry the eastbound track in one and the westbound in the other. Yes it does happen.

If I were to come across a situation of five tracks needing to go into the scenery, I would try to disguise the situation; perhaps a single bore beside a double track bore and a divider of trees and the last two tracks disappearing under an overbridge and town buildings. Tracks can be hidden by disappearing behind trees into a "cutting" that doesn't admit to being a tunnel. Tracks that are only used for freight can go into a warehouse. Another possibility might be to bring the tracks together before the tunnel-mouth (normal prototype proceedure) and then separate them again inside the tunnel. Even just grouping the tunnel entrances at different distances along the route, with retaining might make the scene more believable.

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Thanks for all the replies so far.

I have seen the stepped arrangement before in one of the model books I have. It is for an overpass on page 33 of John Armstrong's "Track Planning for realistic Operation." It only took a minute to find it!

My layout has a through track at the end, and four yard stub tracks next to it. they are at the end of the layout in an obscure area. So I think the ideas above will work well.

snipped-for-privacy@email.ads (Ken Rice) wrote in news:mtMde.5920$k01.2712@trnddc03:

MAX Light rail line under the Portland West hills. Two round bores side by side. It's quite obvious on the western portal as you can see the round liners poking out from the hillside.

Yes, Amtrak runs through several parallel tunnels over Donner Summit in the Sierras

Two single track tunnels side by side are often seen in Japan, usually because the line was originally single track, when doubled, an additional, separate tunnel was bored. In these cases the original portal is often of stone, the newer one of concrete. Regards, Bill.

side-by-side

Pretty much all of the London Underground, although the tunnel portals are usually double trackwith seperate tunnels starting a few yards in.

I *think* that there's some side-by-side single track tunnels on the main line just north of King's Cross too.

I'm not near there either but I got friends up that way. Yeah - leaks leading to flooding, and an engineering firm said that they can no longer "certify" it. This after a multi-billion dollar expenditure.

Tepid Pilot

Windsor to Detroit under Detroit river two bores..

Steve

They sure do Gordon, I used to ride it all the time to and from work when I lived in Portland and worked out at intel. It was always nice and cool in that tunnel too. :-)

In Pa near Glitzin there is a tunnel with two tracks and a seperate bore for a single. Total of three tracks. At this time the single bore is shut down.

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