Building a highway tunnel.

Discussion in 'HO Scale Model Trains' started by green_elite_cab, Jun 22, 2005.

  1. green_elite_cab

    green_elite_cab Keep It Moving!

    hi folks!

    haven't been here in a while, but the forum i was has been dead, i was curious if any of you know how i would build a higway tunnel.

    my layout is built on a flat 4X8 sheet of plywood, so i would assume i would have to cut into the benchwork. can anyone help me with this? how would i make a down ramp, how would i cut the plywood?

  2. Ralph

    Ralph's for fun!

    Yep, sounds like you'll need to cut into the plywood, probably with a jig saw to create a roadway that will dip below track level. This is a pain with an already constructed layout as the power tool will simulate a 9.5 scale earthquake on the layout. How about a highway bridge over the track instead?
  3. green_elite_cab

    green_elite_cab Keep It Moving!

    because there isn't enough space to build a ramp to get the highway bridge tall enough to get over the catenary once its built. luckily though, nothing but my track and roadbed is actualy attached to teh halyout, i haven't mounted any buildings or scenery. i figure now would be a very good time to cut into my layout!

    how would i detail the interior of the tunnel?
  4. green_elite_cab

    green_elite_cab Keep It Moving!

    also, there is a joist in the way of the proposed higway tunnel. but if there is no layout to support above th area i cut, it isn't that bad is it? its on part of the ramp section that goes down. i imagine it wouldn't be that bad, and i would have to cut all the way through the joist.
  5. SAL Comet

    SAL Comet Member

    Ha Chris, A circular saw would cause less vibration, mabye a 5 or 6 on the Richter scale.
  6. TomPM

    TomPM Another Fried Egg Fan


    Do you have any pictures or a track plan you could share?

    In the real world railroads rarely built tunnels for highways under the railroad. These were generally maintenance headaches for the railroad. Since they went under the railroad the railroad had to maintain them which cost the railroad money. Also the railroads rarely used tunnels. They would use a bridge with retaining walls. The bridges were generally as short as possible usually one lane wide.

    Railroads favored bridges because they could usually force the maintenance of the highway bridge off on whoever maintained the adjoining highway. If the bridge was not maintained and its condition affected the railroad the railroad could have the bridge closed and the repair costs born by the highway agency. The railroad’s excuse would be it carries a road not our railroad. Well enough about history.

    Could you curve the road and have the bridge ramp run parallel to the tracks and then turn to cross the track and then have another parallel ramp. I have seen many cases where there was done to eliminate grade crossings on the NEC. Eliminating the grade crossing is what it sounds like you are doing.

    If you can’t build a bridge over the tracks you would be constructing one under the railroad. As I said the prototype would most likely build a bridge. It probably would be the tracks sitting on top of some big girders or a thru girder bridge. In some cases it might be a concrete bridge. The span would most likely be no more than 20 feet. The grade on the roadway approaches would be no more than 6 to 8%. The clearance under the bridge would be any where from 10 to 16 feet. The clearance would depend on when the bridge was built. The earlier the lower the clearance would be. As far as detailing the area again the age would help determine that. A structure built before WWI would most likely be stone masonry abutments and retaining walls. If it was built between the wars it could be either stone masonry or poured concrete. If it is after WWII it would be poured concrete.

    If I can find any pictures of what I am talking about I’ll post them.
  7. TomPM

    TomPM Another Fried Egg Fan

  8. Doc Holliday

    Doc Holliday Member

    Try doing an image search for "underpass" and you'll get lots of pics of prototypes, such as this one
    or this one
    These show a couple of examples of how the side walls retain the ground. It sounds like you're gonna have to cut out a large section of your plywood and redo the joist to move it out of the way. I'd use a jigsaw with a fine toothed blade to cut the plywood and go REAL SLOW. For the ramps, you could either bend a thin piece of luan or masonite or carve into a thick layer of foam.
  9. green_elite_cab

    green_elite_cab Keep It Moving!

    i need to upload the pictures, and will do that tommorow morning cause its getting late as of the time i post this. however my model railroad of more modern times, basicly from the beggining of conrail to now. its loosly based on the north jeresy coastline around the outerbridge crossing in south amboy on one side, and loosly based on the railroad yards i always see when i pass through newark.

    now i was just looking at my layout, and i decided a bridge might work, and i got a ramp grade that looked about right by useing unbuilt roadway sections from my rix overpass kits, and it might be possible to get it high enought to pass over the catenary, and the only thing is that the ramp might block the veiw the buildings and structures i plan to put around where the ramp would be, but as i type this i grow more and more convinced that another highway overpass might be the simpler way to go.

    i feel a bridge might work for an addition to my layout. one big problem however is that since the other side of the bridge would end in what is currently thin air. i don't want to put in a highway support, because the downtrack veiw from this part of my layout looks really neat, and is a great spot to take pictures of my traisn and locomotives, and i'd just hate to have it block the way. i like takeing pictures of my train as if i where an ho scale person, and i just worry if it might ruin my oppertunites to get a good shot...
  10. green_elite_cab

    green_elite_cab Keep It Moving!

    I apologize, it seems like this phot came out pretty big, and i don't know if it will fit, because i haven't really posted picuters here before. here is orginaly teh place i planned for the tunnel. i penned a rectangle in the are where i was planning to cut, but then decided i might be able to fit a ramp in there. you can see where i placed rix highway sections along where the mainstreet would be. i'd probably move it alittle closer to eth yard, and have one road fork off to where the E-33 is sitting, and another go up on a ramp and over the tracks.[​IMG]
  11. stuart_canada

    stuart_canada Member

    i would skip the tunnel for the automobiles under the tracks, put in a nice crossing, or build an over pass for the trains to go over the roadway. Tunnels under the tracks would just in my opinion would be a waste of space and time. But if you want it, you will build it.
    jsut have to find your materials and cut thru your table top. as for the support under the table, i would have it so the support was as close to the track as possible and not worry about cutting thru it. after all not like your cars are going to be moving on the hiway right?
  12. green_elite_cab

    green_elite_cab Keep It Moving!

    thats the issue though, a grade crossing wouldn't be realistic on a highspeed commuter line that i based my rail road on ( they aren't gonna see the metroliner or ALP44 comeing.....)

    , and until recently i didn't think i could get in a good ramp for a bridge. rember i'm putting overhead on this layout, and it has to be able to get over the catenary, which makes the bridge have to be a little higher than normal.
  13. Pitchwife

    Pitchwife Dreamer

    Hi green_elite_cab. I would cut the entrance to your your underpass on one side only, put retaining walls along the sides of it and put a mirror at the end to give it the illusion of depth. They have something like that in Bend which is about 170 miles west of me or I'd post pictures. Of course theier underpass has to have a side to come out of, where you don't, thus the mirror.
    I would also make sure that the framwork support is beefed up if you have to cut part of it. The old weakest link in the chain thing. Good luck. :thumb:
  14. green_elite_cab

    green_elite_cab Keep It Moving!

    i decided that it might be possible to fit in a overpass, all though i might need to rethink part of my scenery, or it might be a tight fit and a steep hill, but i think i can get it to fit.

    i didn't think cutting into my layout would be a good idea, so i will try and fit in an overpass. i only need to buy one extra rix kit ( or i can be creative and mke my own bridge

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