From where my water level will be to the bottom of the lift span is a shade over 75 feet, and most of my small fleet of vessels the distance from the waterline to the mast top is under that 75 foot. Most are around 60 to 65 feet. Vessels like the Wile E., the Nogero, and the Cussler are all outer harbor berthed. My couple of Tomy Tec tugs and fishing boats will easily clear the bridge along with the bigger 70 foot vessel from a kit.
For the heck of it I went looking for mast dimensions in the vertical scheme of things for fishing vessels of around my size. Seems like 64 feet is about right so a good guess. Plus the scale trawler I built a couple of years ago also doesn't have a mast much over that assuming the dimensions were correct And that was an east coast model of a trawler. Now a tall Pelican sitting on the mast may have to duck its head under the bridge but they will clear. However if I were to replace the top with a single girder span I can gain up to 90 foot of clearance and I will have to look at a number of photos before I decide to do that. For whatever reason I like the look of this sturdy little bridge as is so stay tuned.
Well I went back to look at some more photos and found a few with similar upper works like mine but far more with a simple girder span. Thus I went to work to make the change as seen now. While at it I checked the placement of both hoist houses and the operations cabin, which are still works in progress. Also glued on the bridge pier decks which will have to be trimmed when dry. Next up is the counter weights for each end. No locos or cars running off this bridge because when it is up the counter weights block the openings. And now I have a 90 foot vertical opening so my USCG patrol craft can get in the harbor.which do have tall masts. DSCN0035-8 by John Moore posted Jan 2, 2016 at 8:14 PM
Latest configuration is nice, and obviously workable. I like the way the bridge trusses will rise either side of and above the top horizontal structure. However, a comment regarding prevention of locomotives attempting to go swimming. During mid-lift, neither the bridge nor the counter weights will be blocking the tracks. Thus a determined locomotive, and/or its driver, could easily enter a diving competition.
Only after the fact. And then when I do consider the option, which would be an easier build, I realize that I would need more real estate for the ship channel, and real estate is what I am concerned with saving.
With both myself and the Missus under the weather a bit I haven't done much with the bridge. Did a little work today in some painting and created the counter weights for both towers. DSCN0038-1 by John Moore posted Jan 4, 2016 at 5:47 PM
Photographing black on black I had go into my photo program to lighten some so the structural members I added would show. Used Atlas pier girders. I also added some more concrete at the end to rest the extended track and the piers on. Two more pieces t -10 by John Moore posted Jan 5, 2016 at 1:01 PM o add then I can set the rest of the components on.
I'm a bit confused by the pictures. How big are the counterweights? A lift span that big wouldn't take much on either side to balance it. The long Cape Cod lift bridge spans 544' and the concrete counterweights look comparatively small to me. There is definitely a period when the span is lifting and the counterweights are still descending. I believe the span weighs 2200 tons, so there would be approx. 1100 tons on each end, perhaps a bit more if the default position is "up." I'll have to look at my pictures at the size of the weights.
If you go back to the first page of the post Kenneth Anthony posted a picture of a bridge in Texas so I may have it a little to large. But it takes the railroad monad nicely though. Anyway here is the counter weight to give your opinion on. DSCN0048-1 by John Moore posted Jan 6, 2016 at 10:00 AM
Not entirely true. I started building one for a layout I was building and got the main span all done. What I did was took a Kato truss bridge and cut 3 trusses out of it to shorten the bridge a little. The only thing I wasn't sure about is how to make the swing mechanism. After a couple failed attempts I think I have an idea that will work. Ryan
I have thought of a center swing bridge but my track plans are tight and and the harbor real estate tighter still and the center span eats up space. In fact BN replaced a center span with a lift span not long ago and they gained a considerable space in the ship canal with that center pier out of the way. My little span takes up just 6 3/4 inches of real estate and the channel comes out at just a shade over 65 NSFT which suits my purpose. If I was going to do a center span I would consider using the Atlas turntable as a starting point and have an operating swing span.
Finished the vertical lift bridge after making some adjustments to the counter weights. DSCN0049-1 by John Moore posted Jan 7, 2016 at 1:08 PM DSCN0050-2 by John Moore posted Jan 7, 2016 at 1:08 PM DSCN0051-3 by John Moore posted Jan 7, 2016 at 1:08 PM The bridge is approx. 6.75 inches long by 4.75 inches wide and stands 6.75 inches tall. It is designed to have a vertical clearance of 9o NSF and to bridge a channel of 67 NSF, the vessels using the inner harbor have a beam not over 39 NSF. There is a small beacon on the operator's stand roof for errant sea plane pilots. A line of bollards will lead up to the bridge footings on both inner and outer approaches. The bridge fits into the plan below at #34 and will fit into several other plans and takes no more space than an Atlas bridge. Img038-10 by John Moore posted Dec 17, 2015 at 5:28 PM
Nicely done, John. Though I'm disappointed that no elevator is evident for the bridge tender's use. The NY Central kept injured MOW employees on the payroll by allowing them to become grade crossing gate operators and bridge tenders. So I naturally assumed that your company would have the same benevolent policies.
Well I thought it but then I just installed a set of controls, in a lock box on the bridge of course, that lets the operator ride the bridge up or down. And since the bottom span nests outside the top, he just steps off.
I have known a couple of fellows who would have simply done that for fun, a few times daily. Their own personal carnival ride. Ha ha....
Well I don't know if I am done or not. I have the clearance for my biggest locomotive, which would be my MicroAce mallet with spark arrester stack and the biggest car which will be 50 footer. Got the small footprint I want by basing it off the Atlas bridge components and kept the channel height and width where I wanted. Now I am sitting and looking at it and thinking that I need a safety rail on the top platform. And if I do that then maybe I'll do an elevator lift on the side, harbor side, but then I would have to extend the walk off that side some. Or could leave it as is, and just have the bridge tested at each change of shift to insure that the safety interlocks are working while solving the way to get operators to the top. Decisions, decisions in the life of a RR C.E.O. I may have to turn this over to my Chief Construction Officer, aka The Big Guy to study. In the scheme of things this is my next to last build as I have an ample supply of structures now to draw on. One last kit remains, the Bartlett which will become marine supply located off the short spur behind the boat repair yard. When I comes time to lay the track on the last layout all I will have to do is place the buildings and do the scenic work in between and around them. I'll be busy packing. still throwing out and giving away, getting a hold of movers to get estimates, and numerous other things that come with a move. So I am going to sit back and enjoy this last month of railroading for awhile.
