I’m running a few articulateds and have a minumum of 3" separation between track centers.
I’ve been looking online and in Walthers for wider/ 3 or 4 track tunnel portals but haven’t seen anything other than single and double track protals. I’ll use several single portals or kit bash something but would much rather find a RTR/manufactured portal if one is available. Thanks.
I have never seen a triple. I think you will have to ‘cut and paste’ the central top arch out of one and glue it between the split halves of a double.
Would you consider scrounging for a piece of 1" thick extruded foam and carving it to look like what you need? A hobby knife, with some patient whittling, will turn out a nice portal, and you can measure and shape as you wish for your track spacing.
Crandell
I have seen some seemingly wide two tunnel portals, but not a tree or four.
My guess is you will have to hand craft your own, OR take two two portals and put them side by side, or a two and a single side by side. just be sure to allow for clearances of course whre the tunnels meet.
I looked up CHooch enterprizes to see if they had a tree tunnel portal, no such luck.
Grimek;
There is a material called “sign board”. It is a very high-density polyeurethine and is really nice to work with. Check a sign supply house like maybe Garston Sign (in New England) and see what they have available; or even stop in at an advertising sign shop and they may have a piece about 14 inches square; about what yo uwould need. You could get really fancy and hone up yourcarving skills. I would personally make it look like it was poured concrete. It would be correct for that era. By the way, why would you need a three track portal for a single track application?
Rich
Thanks guys.
That’s what I figured. I thought maybe Pennsy fans might know of something with those triple/quadruple tracks.
I will probably try to meld two together and make a plaster cast from that. I may carve one too and see which works out better.
Thanks for the sign board tip. I’ll check that material out.
Not scenicing for awhile yet so there’s time to try things out.
Rich, I meant that I was considering using 2 or 3 separate single tunnel portals in place of larger “3 or 4 track portals” in one piece. That would be the easiest pre-manufactured solution. I like Chooch products so it would likely be theirs. Any single track (only) portals will probably be theirs.
To make a comment from a prototype engineering end, I think you will find that often there will be parallel tunnels when three and four tracks are involved. Widening an existing one or two track tunnel as traffic increased is a dangerous endeavor. It is safer to drill a second bore beside the first. Even when building new, the clear span to handle four tracks will usually require a lot of expensive reinforcement. Nature abhors a vacuum and a tunnel is the equivalent. Even rock will try to settle down - just ask any miner. You should also notice that the tunnels usually have an arched ceiling since that shape has more structural strength than one that is flat or straight across.
John
Are there any tunnels that wide in the prototype? That is a huge span to support in the real world.
I know some subway stations span that far, but they are not very deep.
The west portal of B&O’s Harpers Ferry Tunnel is three tracks wide. Scroll down to the 11th post.
And you will also notice it is arched all the way across. For modeling you could no doubt cut off and use the vertical sides of a tunnel portal casting designed for one or two tracks but the arch will have to be scratchbuilt.
John