I bought it new from Amazon I believe it was.  It was around $50, give or take.  I can look up the specs tomorrow.

Thank you. I guess that length of "throw" would be important.

@PRRMP54 I'm sorry I haven't gotten back to you with the scoop on the linear actuator.  Things came up.  I will quickly say that, yes the "throw" is a factor, as is the positioning of where it is mounted on the bridge.  Mike figured it out for his, and I made some modifications on the placement since if I remember right my span was shorter than his.  I'll look up the specs and get back to you.

@PRRMP54 here is a photograph with the label from the linear actuator both Mike and I used.  I can't find the receipt, but there is no guarantee that source has them.  I just did an online search for 'linear actuator 12v' and it turned up several sources.  They are all in the range of $30 to $40.

I will have to go buy some lumber to mount the hinge side of the double track bridge and start the roadbed for the other end to settle down in and start the new roadbed there.  I have a few odd scraps of lumber that aren't right for the situation.  I was pleased at how efficient I was with reusing wood in building the layout to this point.  With the high cost of lumber, I have hardly spent anything on that.

Thank you. Hmmm. I wonder how one of those would work for a vertical lift bridge.

Perhaps one on each side of bridge and wired to operate in tandem.  🤷‍♂️

Great work so far Mark! Thanks for the close up photos. I know you’ll work this out carefully and come up with the best way to proceed. Glad you got your laptop back.

Andy

Thank you, Andy! 

I finally got SCARM working on the laptop and can see the latest drawings!  Yippee!!  Also, I stopped by Lowes today and purchased the minimal amount of wood I think I need to continue getting the double track bridge installed.  I consider both of those to be major progress.

Mark, sure is nice to hear things are still moving right along. I also agree that that is a major step, but then again anytime you're still moving forward is a Major Progress! LOL!

@PRRMP54 Dave that actuator is rated for 250 Lbs. If you could build a bracket that set off to the side, kind of like a large woodworking square and could attach that to the actuator. You would have to add gussets to support the weight, but I think it would be a simple build.

Mike, thank you!  I’m glad to hear from you!  I’m sure you have been busy before fall chores need done.  I am racing the calendar to get my drainage improvements done before the leaves are falling.  Some already are falling.  I have grass planted one side of the yard, and am done digging the other.  I just need to fill in with rocks, then cover it over.

Your idea for PRRMP54 sounds like it would work.

Hi Mark, Isn't it funny how you can spend almost all summer working on projects from last winter's list. Then when you think your done its time to start getting ready for winter! Then only good thing is when you're ready for winter its train time with the exception of having to maybe shovel snow.

We are luck here as we really don't have any leaf bearing trees near us, just a lot of fir needles! They stick to everything and plug all the gutters and drains! So that might get in the way also!

As for my idea of the "L" shape bracket for PRRMP54 depending on the length and width, it would dictate how big a gusset you would need to make. It could be made out of steal or if he knew someone that can weld aluminum would be the ticket! light weight and strong!

Thank you for the suggestions. My problem is that the "throw" will have to be at least 2½ feet, maybe a little more as the bridge will be across the main bathroom door. The track will be a shelf setup running down the hall wall. More thought will be required as a hinge-on-one-end girder bridge might be a better solution.

@PRRMP54 posted:

Thank you for the suggestions. My problem is that the "throw" will have to be at least 2½ feet, maybe a little more as the bridge will be across the main bathroom door. The track will be a shelf setup running down the hall wall. More thought will be required as a hinge-on-one-end girder bridge might be a better solution.

Dave, take a look at this. It has a 24" stroke! Like you were looking for! Just depends on how much you want to spend!

PROGRESSIVE AUTOMATIONS 12V Linear Electric Actuator - (24 inch, 200 lbs.) Low-Current Rating DC Motor & Durable Stroke. for Automotive, Industrial, Machinery, Home, Robotics Usage. PA-03-24-200

@mike g. posted:

Dave, take a look at this. It has a 24" stroke! Like you were looking for! Just depends on how much you want to spend!

PROGRESSIVE AUTOMATIONS 12V Linear Electric Actuator - (24 inch, 200 lbs.) Low-Current Rating DC Motor & Durable Stroke. for Automotive, Industrial, Machinery, Home, Robotics Usage. PA-03-24-200

Thank you. I went on their website and found one that just may be better as it has a longer throw:

Model: PA-14-40-50

Thank you Mike for coming to the rescue!  I hope the bridge works out for you, PRRMP54!  Please keep us up to date right here!

Just trying to help out where I can!

You do it well, Mike!!

I have been slowly getting the double track bridge installed on the layout, but didn't have much to show.  This past weekend, I got the bridge installed where it lifts up and down and isn't going anywhere.  I made some wood brackets and used the hinges I bought last year that Tom @Gilly@N&W suggested.  Yes it looks a bit ugly, but the bridge is solid and doesn't twist at all when moving up and down.

I did have to sacrifice some of the area that was going to be the boardwalk over to the bridge, but I'll get something nice figured out to disguise the hinges.

The project did not come without a casualty, however.  Not me, but the small, lower track truss bridge.  I do not know how I miscalculated or didn't see ahead of time.  I had actually checked for enough clearance.  When I ran the bridge up for the first time, I heard a crunching, snapping sound.  I was actually glad to see it wasn't the double track bridge!  Instead, the lower bridge truss got caught on the wooden bracket for the hinge in the lower left of the first photograph and, well, I'm not going to show what it looks like now.

I went back to the three through girder bridges I had toyed with using a long time ago.  Even when they are repainted, I don't like them.  I'll come up with something else.

There is a problem though with the overall design.  The double track bridge with the plexiglass stabilizing structure is a bit unwieldy for the arm that lifts it up.  The linear actuator is rated to lift much more weight, but the heavier and wider bridge puts a strain on the lower bridge structure that the actuator is bolted to.  Here shows where it is slowly splitting the wood due to twisting that we were concerned about on the double track bridge.

I planned on rebuilding the wooden structure with the plexiglass strips Mike @mike g. sent me, then use  metal plate for the mount of the actuator's arm.  Hopefully that would be sturdy enough to handle it.  It has occurred to me that it still would put a strain on the structure or the linear actuator.  I could move the actuator over to lift the double track bridge, and then lift the smaller lower bridge by hand.

My version of the infamous Pittsburgh "Bridge to Nowhere"

Wow, Mark, your bridges look great in the pictures, and I admire your ability to concentrate on how to solve this engineering process  where both bridges both do their jobs. Using the hydraulic lift is a cool idea, and one that should be very useful. Your layout is looking really good and I see a lot of progress. Believe it or not, the construction phase of building a layout is the most fun, and when it works it’s very satisfying. Good luck with this part of the project, I’m sure you will figure it out. Great thread, very interesting model railroad. See you in April 2023. Happy Railroading Everyone

Mark the double bridge looks great. Glad that you have about figured it out.

One day we are going to come back to this and borrow some ideas. We will have two bridges to make work.

Mark,

Things look like they are moving along with the bridge installation.  Keep us posted on your progress with it. I love bridges and it looks like between the girder bridges and the truss bridge there will be some good railfanning opportunities.

Dave

The bridges look fantastic…….those hinges have served us well on the modular layout……

Peter

Mark, Great job and when I get to the point of the lift bridge I will be referring to this thread A LOT! Keep up the inspiring work.

Hi Mark, I am with everyone else, the bridge looks great! You can just move the actuator to the double bridge and make an arm to life the single track bridge. I use my actuator to lift 3 bridges at the same time. A double track bridge like your a girders bridge and a road bridge. I will try to get you a photo this morning. You have plenty of power!

@Mark Boyce

I can see a lot of work in that! But the end result is great!

Glad you got it all figured out Mark. The time taken to do the engineering paid off.

It's going to look great when it's done.

Bob

@Mark Boyce

Big project Mark. I know those lift bridges can be problematic.  There is a lot of tension that needs to be balanced.  Hopefully, this will last a long time.  And it looks great!

I wonder whether using plywood is contributing to the twisting and splitting and whether using metal and/or hardwood, as you suggested, would eliminate that.

Hi Mark here are a couple photos of all 3 bridges.

You can make your arm, or arms needed to lift all your bridges together.

Looks great Mark. Hey, when you end up on the scenery end of things, are you planning to disguise the hinges? If you do, maybe use some rubber brush like lichen or such so this way when it is up, it should not cause damage(hopefully). I would think painting them would probably be good to help hide them as well, but naturally that depends on if you are.

Wow, What a response!!  Thank you, everyone!

Larry, the engineering process has been more trial and error that figuring it out ahead of time.  Many thanks to Mike for the initial concept!

Bill, You helped me getting the switches and power wired through the AIUs, so I would be glad to help any way I can on the bridges.

Dave, you are right the bridges make for great railfanning and photography.

Peter, yes those hinges look like they could lift anything you could possibly build.

John, I'm glad you will be able to make use of the bridges as well.

Leandro, It has been a lot of work, but worth it in the end.

Mike, I do think moving the actuator under the new bridge would be the way to go as well.  Your three bridges look great!

Bob, seat of the pants engineering.  Once again, I have a lot of extra drilled holes that now aren't used.

Wood and Richie, yes there is twisting that needs balanced.  Richie, you are absolutely right, it is plywood that is splitting out.  The whole wooden frame for the smaller bridge twists as the bridges lift.  I have plexiglass parts that Mike cut for that bridge as well.  I have steel plates to use to mount the actuator arm on, so when done, it should be much more stable.  Call the first installation a prototype or beta.

Dave, yes, some scenic material would take the flexing as the hinges move.  I am going to paint the metal and wood black so that doesn't show up as well.

Mark, just a few adjustments to make and then you’re home free. If you do decide to go with hardwood instead of plywood as Richie suggested, I’d recommend Maple. It’s a sturdy, dense, and strong wood.

Andy

Andy, thank you!  I appreciate the suggestion of maple.  I removed the wood frame for the lower bridge and installed the plexiglass one.  I have not made a panel for the top of the linear actuator to attach to.  I have a metal plate, but I hate working with metal.

Mark, Glad to help. I prefer wood too.

Andy

I moved the linear actuator to the heavier bridge.  I used a piece of pine, just to see if the concept works.  It works great, but since I don’t have limit switches setup yet, I won’t take a video.

I tried two methods to extend an arm from the higher bridge to lift the lower bridge, but neither left enough room to walk easily through the 27” opening.  I discarded both ideas.  I may just buy a linear actuator for the lower bridge, and quit burning the few precious brain cells I still have!  😆

Here is the lower bridge with half-inch wood between the plexiglass and the old through girder bridges.  I still need some roadbed and track.  I’ll work on getting the correct roadbed thickness before pulling the two P&LE bridges for painting.  I need to figure what matches since I bought the Western Maryland bridge pre-painted.  Or, I’ll leave them as is if I find a replacement I like better.

Mark, I’m fascinated by your expertise and perseverance. You are very impressive.

Jay

Thank you Jay!  I think the perseverance outweighs the experience.    However, thinking on it, I did install the old bridges last year.  I guess that does give me more experience than I first thought.  These two have gone a lot easier than the original installation last year. 

Mark

Another way is to install a two-pullies in the ceiling. attached a cable to both sides of the bridge and connect the cables to a motor either at the ceiling or below.  Then add cut-off switches to stop the motor at the up and down positions.

This is a thought experiment; I have not tried this approach.

Alan, the thought experiment is an idea that I think could work.  I have seen where people have attached cables with motors to lift layouts to the ceiling in their garage when not in use.  The bridges would be easy compared to that.

I ordered a second linear actuator yesterday evening.  It was about $40.

You could do it with one pulley using one cable and Y-connector attached to the two cables fixed to each side of the bridge.