Hi all.
I recently build myself a wooden tunnel portal for my garden railroad. After I finished it I got thinking about finding an image of a prototype. After a search on google all I could find were stone or cement versions. I see plenty of scale model wooden portal versions. Can anyone point me to a prototype image?
Thanks
That is a really good question. I just did a search myself and nothing came up.
One would think that somewhere in America where wood was abundant that somewhere sometime a tunnel portal would have been built. There are plenty of retaining walls, snow sheds, trestles and bridges that are made from wood so there has to be a wood portal somewhere that would have been put up to keep falling rocks from landing on the track.
I’m thinking that wood tunnel portals were not a thing because of the risk of fire from a steam engine passing underneath and belching embers. ?
I have 11 wood portals on my RR and one cement one. Maybe I should rethink this??
Mud tunnel on the Cumbres and Toltec is the only wood one I can recall. I suspect any wood ones have been long replaced with concrete or stone.
I agree, very good and interesting question. So I did some quick digging myself.
The last one looks braced with steel gussets but appears to be wood and still in use with BNSF.
Thank you all for your searching. I guess now I will have to make some cement portals.
Steve
Many of my portals look like that. I prefer the wood to the cement. Wood is easier to work with than cement or foam board cut and painted to look like cement/rock.
It is your RR so your rules.
i like to have both.
depending on the landscape and setting.
eastern US (or CS) with fake (foam) stone portals, western settings with wooden ones.
tunnels are the best way to camouflage the short distances on indoor layouts, creating separate “dioramas”.
Let me do some digging. Tunnel 4 up on Stampede Pass is a wood timbered tunnel. I know because I’ve gone through it multiple times. I’m sure there is photos online just have to find them.
The wood-vs-concrete/masonry portal question can be related to the period involved. For earlier RR’s like the CP & V&T, concrete wasn’t an option, and masonry was likely a matter of budget. Here’s a V&T wood portal.
Sparks flying from the stacks was an issue for the early lines, and the V&T had its share of tunnel fires. In the above pic you can see the metal lining applied to abate that issue.
I’m no expert, but I’ll suggest that the portal architecture was related to the ground being tunneled through. If really stable hard rock, little or no lining was needed, and sometimes no portal structure was needed either.
However, the portal’s job, in addition to stabilizing the mouth, was often to keep rocks & etc. on the hill above from rolling down onto the tracks.
FWIW, a hardrock tunnel was of course the most difficult to bore. But afterwards, it was super stable. Here’s a shot of the CP Summit Tunnel. The portals have had concrete boxes applied over the track (likely for falling rock deflection), but the interior is still solid after about 165 years.
For MIK 2018 I built this wooden portal. I too had a hard time finding a prototype and ended up basing it on one built by Ray Dunakin.
Thanks for the info. Cliff that is the first picture I’ve seen that some what looks like the scale model version. Craig the image you show really shows how the structure is made to deflect falling debris.
Some times I think I put too much thought/effort and time into too small of a detail.
Steve
Steve,
Tunnel 4 is part tunnel, part snow shed. Funny story to follow. The tunnel was supposed to be replaced with a concrete structure but the RR decided it was to expensive so they redid the roof. About this time, they started running double empty grain trains (220 cars vs the normal 110) over Stampede. There’s a defect detector prior to the tunnel that your supposed to stop for if a defect is found to protect the tunnel. Well with the double grainers, the train is both in the tunnel and going over the detector at the same time. So the RR said, it’s not Tunnel 4 anymore but a snowshed. Detector rules only apply to tunnels and not snowsheds. 
This tunnel is lined the entire way with wood. The big tunnel just a mile away is concrete lined for a bit and then turns to bare rock.
