Double track inside a portal becoming single track outside the portal

Digging tunnels is EXPENSIVE! Better to go single track in the tunnel if at all possible as this makes the tunnel about 1/3 cheaper than the double track. Even the Waylong (Tehachapi Loop) tunnel is single track with the siding starting right out of the end of the hole and continuing almost to the next tunnel above Waylong. Even that Waylong tunnel, which is artifically made was done as a single track tunnel.
-- Why isn't there an Ozone Hole at the NORTH Pole?

Bob,
I realize that, as I said, "My intuition tells me it was probably common the other way round". However, there are occasionally things that get done that are counter intuitive. Pehaps with good reason ... perhaps not?
I was just wondering if anyone was aware of an example of this particular possibility, as wrong as it seems on the face of it.
Paul

OK, here's a U.S. prototype, but you may not be happy with it. Many years ago, I remember riding on a 15" gauge RR at an amusement park, or perhaps it was a zoo. It had a large single track oval that went to double track in their "tunnel" (which doubled as the train storage shed). I remember being able to see a second train set on the other track through the gloom of the tunnel, wanting to ride it too, but being told it only ran on very busy days. Gary Q

"Geezer" wrote in news:- snipped-for-privacy@adelphia.com:
When they first opened, the mainline track at Opryland (Nashville, TN) went through their engine house and you could see the second engine sitting on a parallel track. Seems like they changed that after a year or so. Moot point now, since Opryland is gone, replaced by a shopping mall. What a waste of real estate!

Ok, it's what I asked for but, not what I was looking for. A commercial railroad (hmm, not sure that's expressing it correctly either) is what I had in mind, standard gauge would be best.
HOWEVER, it is an example!!
Thanks, Paul

John Allen once said that no matter how strange your model is......there is a good chance that a prototype exists or did exist. HZ

Exactly what I'm hoping for. A railroad with say, at least 100 miles of track, that had a single track becoming a double track going into a tunnel.
The change to the layout is going to have a switch which will fork the single track and then each of the two new tracks will go into different portals which are going into the same hill but, going different places.
I was just wondering if there was an actual prototype that did the double into tunnel thing.
Paul

OK, now I feel I owe you to make up for my last dumb comment. Could you scenic the approaches to the tunnel as if they were double track, with a crossover (one working turnout, one fake) just outside the portals leading to your functional single approach track? The second dummy track could run a short distance to an appropriate scene divider / scenic block, and be sceniced as if out of service for cleaning up a wreck, or with a dummy train forever waiting for the signal to enter the tunnel, or for heavy maintenance like replacing all the rail, etc. Then you don't need to find a prototypic excuse for the unlikely track arrangement. Gary Q

"Paul Newhouse" wrote in message news: snipped-for-privacy@comcast.com... is......there is miles into but, the Paul.
I seem to recall you can find an example of a single line splitting and going off into different single line tunnels near Harper's Ferry, among other places. But this is a different thing than what you described, a single track splitting to two that both go into the same double portal, originally.
Len Head Rust Scraper KL&B Eastern Lines RR Museum

2000
Common error but it is an error. It is Walong, not Waylong. It was named for W. A. Long, i.e. Walong.

Yes, we have several examples of this, thanks for pointing at another one to look into.
Right, we aren't doing it.
This all came up because of some changes to the layout. We were going to put he switch outside the portal and run double track into the tunnel. We didn't want to bury the switch expecting future maintenance requirements. With the scenery removed the installation isn't to difficult but, with scenery reinstalled maintenance would be exceedingly difficult. We shyed away form a liftout since they tend to be obvious (without a great deal of care and planning) especially where this one would have to be (it's very close to the aisle so visitors would have a bird's eye view). We have a couple of other liftouts close to the aisle but, the lines are easy to camouflage since you would expect lines where the edges of the liftout meet the layout (edges of streets and such).
After we got the track in place we realized that the double portal would look funny (nevermind the fact that you would not expect that in to occur in real life), so we went to a dual portal scheme since the diverging tracks do, in fact, go to different places. BUT, during all of this I suggested that with all the wierd problems and requirements that railroads face the split before and double into a tunnel may well have happened ... somewhere? I was just curious if anyone had an example of this, L@@K RARE, occurance.
Paul

Sounds like the Detroit Zoo's amusement railroad. There were several tracks inside the tunnel / train shed / enginehouse. Some were used to store spare trainsets and equipment.
Dan Mitchell ============

On Tue, 05 Apr 2005 09:17:19 -0500, snipped-for-privacy@pimin.rockhead.com (Paul Newhouse) wrote:
Does the line diverge and go off in two different directions, or is it double track inside the tunnel and single track at both ends?
If the line does diverge, then there is no real problem.
If the line does not diverge then simply brick-up the other portal, run single track, and say that double track was originally planned, but before it could be installed the plan was changed. The bore was only partially completed and dead-ends 300 feet inside the portal. That takes care of the double track portal.
If not bricked-up, then the other portal could be sceniced for as far back as the eye can see as an unfinished bore. It could also be made into a signal maintainer's depot inside the unfinished bore. An access road coming in from a hidden point, and a wooden or brick façade in the portal with double doors wide enough for a truck or motor car to get inside. A motor car setoff on the track would complete the scene and- voila! No more tunnel "problem".

Or the one in St Louis' zoo and also at Audubon Park Zoo in New Orleans as well as the one in Atlanta too. I wonder if every zoo has a choo-choo? San Diego?
CH>

Yes.
It does and the layout is all set. I'm just pursuing a question that came up before we settled on the current design (The current design is two diverging tracks and two separate portals).
Paul

Are there any prototype examples of triple-track tunnels?

Well, again, I'll bet there has been at least one, sometime, somewhere. I haven't really been looking for that. If there isn't a single track bearing down on the portal I skip that pic. If there is a one track approach I check to see how many go into the tunnel. So far only single track tunnels with single track approaches. LOTS of multiple tracks converging down but, that's what everyone in this thread was indicating they expected.
Paul

snipped-for-privacy@pimin.rockhead.com (Paul Newhouse) wrote in news: snipped-for-privacy@comcast.com:
On the double track tunnel question, I'm surprised that none of our British friends mentioned the Chunnel. That's at least two tracks.

Its actually twin single bore tunnels, approached by several tracks, just like umpteen tunnels elsewhere. How is that relevent to the OP's question?