I have the same issue to deal

I have the same issue to deal with, so I'll be paying a lot of attention to any accomplishments you are able to share.  Mine is double track, but only single level.

I'm thinking I might be able to do an entire river scene with several pillar supported bridges across the space.  The entire module type section would raise straight up.  I don't want anything showing above the 53" high layout surface, so the scene would need to have it's mechanism below grade and move straight up as a unit to allow room entry passage underneath.  When lowered, it would look just like any other section of the layout.

I'm envisioning the support and lifting device could be constructed with aluminum shapes from the hardware store.  Somehow, it would telescope to accomplish the lifting.  I'm thinking motorized, of course.

My motivation is that in looking at the various bascule bridges, I might not live long enough to get it built. 

One interesting page I found, not so much relative to my idea described above, but interesting nevertheless:

https://sites.google.com/site/modelrailroadlayoutbuilder/model-train-bridges

Vertical Lift Bridge

Now that you mentioned it, a vertical lift bridge just might be easier to construct for the entrance......no worries about locating pivot points so accurately for track alignment and support in the middle of two side sections, etc I like that idea.
 

I could stack one on top of the other for my double deck trackage, and sort of hide (disguise) the connection between the two layers. Have to see if I have room under the ceiling height.

I'm looking to make it simple (KISS principle), so NO mechanization,...just a nice smooth raise or lower by hand for multiple entries  

Mine will be double tracked also at both deck levels.

I even have a piece aluminum channel that might well serve as the 'roadbed' for such a bridge. I'll take a photo later today

Lift Bridge Ideas

Number D is not too bad
 

I have some Atlas curved cord bridges I could build this one with...

Double Track Bridges

quote 'lifted' from my old Central Midland Layout posting....

Obviously I like bridges on my layout. Did you count the number I have there?....and only two of them are the same....the 2 modified Atlas Curved-Cord bridges.

6 bridges total

FAKE BRIDGES
Several of my bridges were not really bridges in the truest sense,.... they didn't have their bottom structures.

Both of these were the double-track bridges that I kit-bashed from single-track Atlas/Roco Curved Cord Bridge kits. I simply took two single track bridge kits and 'doubled' the upper connecting beam structure to effectively provide for a dbl track spacing between the curved cord beam structures.

I left the bottoms out (to be used on other projects*), and just relied on the roadbed to provide support for the track of the bridge. I glued four 'locating pins' onto the corners of the curved cord sides, and these plugged into 4 holes drilled into the plywood roadbed. This kept the 'bridge' properly located, and its side frames properly spaced apart such as to not interfere with the passing trains.

One of these dbl track bridges was set up as a safety device,....that one against the backside of the layout right at the point of the crossover switching between the 2 mainlines. I had in the past experienced several of my nice steam engines derailing and crashing off the layout onto the concrete floor...NOT a pleasant experience!!   I decided I was going to put up this bridge structure to prevent any derailed loco from experiencing that fall off the side. Strange as it might seem, after I put this 'guard-rail bridge' into place. I hardly ever experienced any other derailments ??

That 'fake bridge' precipitated the idea of a stream/river running under it and out into the 'country backdrop'. It also meant I have to have another bridge for the inner track,....thus the 'deckbridge' to allow for variety.

The other 'fake bridge' came about as a result of my adding the Walther's double track truss bridge for the dual tracks I wanted to have enter into the turntable zone. Since I had that bridge actually spanning the lower tracks, its only naturally the my yard entrance tracks would also be spanning those mainlines below. The 'fake double chord bridge' was the easiest way to do this without tearing out the subroadbed and replacing it with an actual real bridge. Besides with all the ballast, and cinders, etc in this yard area, no one would ever tell there was no bottom on that bridge. I also had to pay particular attention to the exact location of those bridge side frames so as to not interfere with the swinging passenger cars and articulated Big Boy loco that would come thru that trackage.

Train Shed Door

Here are a couple of photos of my train shed doorway, (disregard the former cardboard shelf mock ups,...things have changed)
 

One thing that I think has to

One thing that I think has to be considered on a lift bridge is that the two ends can't get out of sync.  With dual motors, if one failed to respond for any reason, the other could continue the lift and create a lot of damage.  Somehow, it has to be driven with one motor, IMO.

I'm thinking that with an entire module raising, I can build a river scene underneath that raises as it's part of the module.  With just a lift bridge, the underneath becomes empty space.  Not a deal breaker, just something I'd like to have in order to make the lift bridge complex a real artistic part of the scene.  I've seen some real neat rivers and bridges on the forums, but not so many that can move out of the way for human passage.

Mianne Lift-gate

Brian, are you familiar with the Mianne Lift-gate?  It uses a small electric winch under the adjacent benchwork with a couple of pulleys and the lift section guided by four drawer slides.

It was mentioned in this thread.  https://forum.mrhmag.com/post/does-anyone-have-an-electric-liftup-that-is-simple-12210055

Lift Gate

Thanks for that reference Dave. Just the sort of thing(s) I wanted to explore.

I only had a short time to look at my situation yesterday, but I may give it some more thought today. It does appear as though I may have some overall height restrictions on some of the options. That lift-gate idea might be a way around my restrictions.

Another thought entered my thinking,...somehow melt the bridge structure itself (minimized) into a backdrop painting on the wall of the door. .....
.....Ie, the back wall of the door would be painted as the body (river or bay) of water, and the bridge might simple be a trestle across it with multiple legs that don't actually touch on any base, but appear to do so as a result of the water backdrop??
 

Don't know that I have that conveyed that thought properly??

Houghton, MI vertical lift bridge

Brian, here's a prototype for you:

https://www.mtu.edu/webcams/fund/motion.html

Largest vertical lift bridge built 1960.  The lower deck once had RR tracks but gone today.

Robert

That's US41 same highway as in Florida.  It ends about 50 miles to the left.

FL lift bridge?

Link in question?

View of Portage Lake Lift Bridge and the campus from the Michigan Tech Fund offices in Hancock.

https://www.mtu.edu/webcams/fund/motion.html

Jacksonville Train Bridge

Jacksonville FL has big river to cross, so I thought I might google it,...

http://historicbridges.org/index.htm

My Entrance Doorway

Here with just two of those alum extrusions (uncut in length) strung across it at the two levels

The extrusions I happen to have collected,...

perhaps side by side...
 

Lift bridge in a model railroad

Brian,

The Paradise & Pacific Railroad Club in Scottsdale, AZ uses a lift bridge to access the member/operator area of their club.  The more able bodied members duck under, but those with bad backs or knees use the lift.

The lift is counter-balanced, no motor.  Electricity to the approach tracks is cut off when the lift is up.

These pictures are from their web site http://www.pandprr.com/pandprr/Home.html

They were take at the opening of their layout in a new building in 2010 and is still in operation today.

The layout is O scale, but the concept should work for you.

Ray R

Lift bridges

Brian

A modeler a year or two ago use heavy duty draw glides, the type that mount on the bottom vice side of a draw., to construct a verticle lift gate.  The article was in Model Railroader magazine

Ed

Lake Street Bridge

Not solely a 'rail bridge', but

http://historicbridges.org/bridges/browser/?bridgebrowser=truss/lake/
 

a video of that bridge in operation,...
http://historicbridges.org/bridges/browser/videos.php?bridgebrowser=truss/lake/&videonum=4&videoext=m2ts&w=800&h=450

A fancy bridge may be nice,

A fancy bridge may be nice, but since it is at an entrance to a layout inside a small shed, personally I'd suggest building something rugged which can take the occasional bash since likely that is what will happen sooner or later.  A fancy lacey bridge may meet a tragic fate in one of the many ins and outs. 

Just predicting the future and wanting to help you "future-proof" the layout.  I'd put a fancy bridge somewhere less prone to accidents and damage.

Agreed

I'm thinking i agree with you Jim. ....just brainstorming

Hah hah.  Let the storm

Hah hah.  Let the storm happen in your brain, and not the layout, or in this case a fancy bridge that might end in tears.  

Brain Storming those 'Bridges' across the Entrance

Construct a light weight, rigid, rectangular metal frame that would be as wide as the entrance opening I intend to have (36"?), and tall enough to have all 3 track levels (staging, bottom deck, top deck) attached to it,...plus extra height to go above the shed's door to reach a horizontal hinging location above the door.

In other words the top horizontal leg of that metal rectangle would form the rotation axis about which the 'frame' would rotate upwards (swing upwards) towards the ceiling. Then it would be only necessary that the width of the bridge structures, etc be limited by the clearance to the top of the ceiling when the frame is swung upwards into it's raised position.

These 'bridges' could be of many different types / styles, and not to limited to their scale heights. They would be attached to the metal lifting frame via their sides facing the frame, leaving their opposite sides facing the room. Only the bridge structures themselves would appear to cross the space between the open spaced metal frame

The inside of the shed's door would be painted as a body (river or bay) of water, and would act as the backdrop for the bridges when it was closed. When the door was left open there would be hollow spaces between the bridge structures that a person could view thru to the inside of the shed.

The bridge might simple be a trestle across the water with multiple legs that don't actually touch on any base, but appear to do so as a result of the water backdrop?? .....somehow melt the bridge structure itself (minimized) into a backdrop painting on the inside face of the shed's door. .....

PS: I had originally thought of making that 'rectangular frame' a solid piece of plywood with the backdrop painted on to itself. But that would mean that even with the shed's door open, no one could see inside. So that's when I began to think of a 'hollow core' to that framework.

Another attempt at explaination of lifting bridge idea

No I have not set down and figured out the details of this lifting bridge arrangement yet.

I was looking for an image that might help explain what I have in mind but didn't come up with a good one yet. Do you know what a Murphy bed is? What I have in mind is somewhat akin to that, but it will hinge at the upper level and 'fold up' to the ceiling rather than down to the floor.

It would be like taking a flat piece of plywood 36" wide, and approx 38" tall, and hanging it vertically over the my sheds entrance via a 36" piano hinge along its top. Then attach the 3 bridges by glueing one of their sides to the flat piece of plywood (sort of like 3 small shelves deep enough to hold 2-3 tracks across them).
 

This would piece of plywood with the bridge structures stuck on like shelves would be hanging vertical when the trains were operating, and would hinge up to the ceiling when entering/exiting the shed.

There would need to be a slight taper to the depth of the shelves (and tracks mounted on those shelves) to facilitate the the swinging motion of the flat panel of plywood.

or an attic door image
 

Emergency exit?

From the photo you posted earlier your shed door opens out?  Will the hanging board the shelves are on leave easy access to the latch for the door even when in the down position?  Are you agile enough to scoot out under the shelves if something catches fire while you’re in there?

elevator?

have you considered using columns acting as guides for the shelf to travel up/down on?

Door Latch & Escape

Here are a couple of photos of the door latch. It hooks around the wooden door frame at a spot just below the maindeck level support beam,...thus it is reachable from inside the shed via the slot created between the main deck plywood and the staging level plywood,...and all of that in this area is a very thin depth of only 7.5 inches that handles the double track mainlines crossing the entrance opening.
 

Here is just a rough mock-up of flat panel that would hang from the front wall by some sort of piano hinge (blue tape). It would swing up to the ceiling like shown below. It would also be a 'hollow frame structure' rather than a solid board,..to allow for vision in and out when the door to the shed is swung open.

And yes in an emergency I could scoot out under it.

Exits and Elevators

I guess that’s probably good enough for an exit Brian, if you’re comfortable with it.

Greg, interesting idea for the elevator.  I assume you’re thinking something like a cable to each side of the two decks, with stops to let each deck rest at the right height when the cables are slack.  When you pull up the cables (via pulleys near the ceiling?) the lower deck bridge comes up to the bottom of the upper deck bridge which then rides up on top of it?  With suitable spacers to protect scenic elements?  Sort of like the way venetian blinds pull up.

That way might be a little harder overall to build than Brian’s hinged panel idea, but on the other hand since each bridge would be able to sit on it’s own lip on the adjacent benchwork in the down position it might be easier to actually ensure consistent and repeatable lineup with the adjacent track.