mbinsewi I've been watching, could you alternate the sides, using the X pieces, to get the overall length the same? trying different combinations of X peices butted, one from one side, and one from the other side, to get the length? Is scratch building the piece an option? instead of buying another kit? Mike.
I've been watching, could you alternate the sides, using the X pieces, to get the overall length the same? trying different combinations of X peices butted, one from one side, and one from the other side, to get the length?
Is scratch building the piece an option? instead of buying another kit?
Mike.
Rich
Alton Junction
Rich. After seeing your photos, now I understand. It is possible to achieve what you are trying to do without buying another kit but it's going to take some time and patience. If your time is valuable the third kit might be the way to go.
Store bought styrene does work with bridge kits if you need to lengthen anyting, I've done that. When I was trying to kitbash, it was turning a Warren truss Bridge into a Pratt Bridge from kits because it was the right size. I needed a Camelback Pratt for the center section of a three-section series bridge. The problem was the gusset plates being different sizes that become a big problem. These two truss sections are the same sections, the one is just modified. I was 90% there but I said screw it because I had five more to do.
At least I see what you're trying to do now. Honestly I would have to agree with Wayne. Save yourself a big headache and buy the third bridge. You will thank yourself
I foresee you still have a challenge but you can do it. You may want to run a steel rod under your tracks when you get the bridge done. Those HO loco's sure are heavier than the N ones.
TF
TF, thanks for that advice and, by the way, very nice job on that bridge in the photo.
Yeah, I think that the 3rd bridge is the way to go because it is going to be difficult to scratch build the additional center section(s).
OK, so just to clear this up in my own little mind, the X pieces are the same size, so with the second kit, you 2 more X pieces, for a total 4, but you want to make the span longer yet, so you need a total of 6, X pieces, 3 for each side?
I think I musunderstood you as saying the X pieces weren't the same size, is why I suggested the mix-n-match.
The bridge you want to build, is like Frank's? Do you scratch build the towers, or are they from another kit?
My You Tube
mbinsewi OK, so just to clear this up in my own little mind, the X pieces are the same size, so with the second kit, you 2 more X pieces, for a total 4, but you want to make the span longer yet, so you need a total of 6, X pieces, 3 for each side?
Each side of the truss span consists of four pieces, a left side and a right side outer section and a left side and a right side inner section. The left side outer section is mated to the left side inner section, but these mated sections are different lengths. Same for the mated right side sections.
The center x-braced outer and inner sections are the same overall size, but unlike the other other sections of the truss span, the vertical ends of the center x-braced section are not the same width. One end is narrower in width than the other end. So, when the outer and inner sections are mated, the narrow end of the one section is mated with the wide end of the other section, and the wide end of that section is mated with the narrow end of that section.
Whew, that is a mouthful. It is all the fault of the 60/40 arrangement.
mbinsewi I think I musunderstood you as saying the X pieces weren't the same size, is why I suggested the mix-n-match.
mbinsewi The bridge you want to build, is like Frank's? Do you scratch build the towers, or are they from another kit?
Thanks Rich for taking the time to explain, again! I'll have to look at the instructions again, just for my mind. It's crazy that each side is two pieces, being an inner and outer.
Keep us posted, and lets us follow along!
mbinsewi Thanks Rich for taking the time to explain, again! I'll have to look at the instructions again, just for my mind. It's crazy that each side is two pieces, being an inner and outer.
The photo below shows the 8 sections required to complete both sides of the arched Pratt truss bridge.
The photo below shows the 4 mated sections required to complete both sides of the arched Pratt truss bridge.
The photo below shows the 2 completed sides of the arched Pratt truss bridge.
Now, I need to add the two additional center x-braced sections to lengthen the bridge to 30" from the original 23".
richhotrain ....I need to add the two additional center x-braced sections....
And when you do, you can file the vertical members, where necessary, to keep them all the same thickness, or, where they're too thin, add appropriate strip styrene as a filler between the mating kit pieces.
Wayne
doctorwayne richhotrain ....I need to add the two additional center x-braced sections.... And when you do, you can file the vertical members, where necessary, to keep them all the same thickness, or, where they're too thin, add appropriate strip styrene as a filler between the mating kit pieces. Wayne
That's even better, Rich. In the last photo, the joints between the two sections looked a little thinner, although I do realise that they're not yet cemented together.
doctorwayne That's even better, Rich. In the last photo, the joints between the two sections looked a little thinner, although I do realise that they're not yet cemented together. Wayne
OK, I don't own a caliper, but it does appear that all of the vertical members are the same width at 3/16". So, I see your point, Wayne. I need to cut and trim the vertical ends of those additional x-braced sections so that they have the same resulting width as the unmodified vertical members. I believe that my plan for cutting and trimming these additional sections will result in identical widths. But, we shall see.
Cut the x-braced sections from the 2nd kit. Now. to glue them in place.
I was going to suggest modifying it to a Baltimore Truss. I could find a really good picture on bridgehunter.com.
There is so much iron work here, I don't know what I'm looking at
Henry
COB Potomac & Northern
Shenandoah Valley
BigDaddyThere is so much iron work here, I don't know what I'm looking at
THIS was always one of the bridges I found to be fascinating. A bridge within a bridge:
http://www.trainmaster.ch/Z-425.htm
https://www.brasstrains.com/classic/Product/Detail/033937/HO-OMI-GN-BN-BNSF-416-foot-Bridge-in-a-Bridge-WOW
Cheers, Ed
BigDaddy I was going to suggest modifying it to a Baltimore Truss. I could find a really good picture on bridgehunter.com. There is so much iron work here, I don't know what I'm looking at
I successfully completed the addition of the third center x-braced section on both sides of the truss bridge, as seen in the following photos.
Now, I need to tackle one more aspect of the bridge to conform it to the shape of a vertical lift bridge. That will require modifying the angled ends of the sides to box shapes to accommodate the tower cables that lift the bridge.
Looks good so far Richie........
Back to My ship......
Take Care!
Frank
richhotrain I successfully completed the addition of the third center x-braced section on both sides of the truss bridge, as seen in the following photos.
What an accomplishment! Your bridge section looks Factory. You should be proud. You have succeeded in an area where I threw in the towel.
The Webster dictionary should be changed. When one looks up the definition of perseverance, It should read: Rich's Pratt Truss Bridge modification
zstripe Looks good so far Richie........ Back to My ship...... Take Care! Frank
Track fiddler What an accomplishment! Your bridge section looks Factory. You should be proud. You have succeeded in an area where I threw in the towel. The Webster dictionary should be changed. When one looks up the definition of perseverance, It should read: Rich's Pratt Truss Bridge modification TF
Speaking of Webster's Dictionary, I was looking at the various types of Pratt bridges on line, and I was surprised at the number of variations and the names assigned to them. I had actually considered naming my variation as the Arched Rich Pratt Truss bridge once I box the end sections.
Here is the end section of the Arched Pratt Truss bridge, as Walthers designed it.
I need to form a box on the end sections in order to provide a top horizontal surface to connect the tower cables. Here is what I am going for.
This is going to require some cutting and sawing and fitting to pull this off.
richhotrain I had actually considered naming my variation as the Arched Rich Pratt Truss bridge
Nice work Rich. I can see it now...........
" Ladies and gentleman, before you stands a brilliant example of bridge design from the famous engineering father-son team of Caleb Pratt, and his son, Thomas Willis Pratt. I might point out, that a footnote in history gives Thomas Pratt's often rebellious and unrully step child, Rich, credit for the "squared off" end design, allowing for the main span to be incorporated into the vertical lift bridge that stands before you."
mbinsewi richhotrain I had actually considered naming my variation as the Arched Rich Pratt Truss bridge Nice work Rich. I can see it now........... " Ladies and gentleman, before you stands a brilliant example of bridge design from the famous engineering father-son team of Caleb Pratt, and his son, Thomas Willis Pratt. I might point out, that a footnote in history gives Thomas Pratt's often rebellious and unrully step child, Rich, credit for the "squared off" end design, allowing for the main span to be incorporated into the vertical lift bridge that stands before you." Mike.
Rich Pratt
I completed the modification of the four box ends to the bridge. Here is a photo of the completed truss side.
Here is a close up view of the boxed end.
I am pretty pleased with the result. Now, i need to move on and complete the installation of the top and bottom chords, the vertical and diagonal lacings, and then start construction of the expanded girders that support the truss sides and tracks.
You are doing a fine job, Rich......
Take Your time......
Again.... Factory.
That Pratt Bridge has your signature written all over it Rich. I like it
zstripe You are doing a fine job, Rich...... Take Your time...... Frank
Track fiddler Again.... Factory. That Pratt Bridge has your signature written all over it Rich. I like it TF
richhotrain zstripe You are doing a fine job, Rich...... Take Your time...... Frank Thanks, Frank. Your CMR vertical lift bridge is my inspiration for this project. Rich
Thanks, Frank. Your CMR vertical lift bridge is my inspiration for this project.
Rich,
Trust Me! Building that vertical lift bridge, was a cake walk, compared to building the fine detail on My ship....especially in the size of the parts in the etched brass detail:
richhotrain zstripe richhotrain What I fail to understand though is why the kit was designed with that 60/40 arrangement. That complicates the insertion of additional center sections. So, I need to further analyze how to pull this off. I invite all comments and suggestions in this regard. Rich, Like I said in My PM.......The X sections are the main vertical stress part of the bridge. The 60/40 arrangement was to offset the stress on the X sections where the girders would meet, instead of having them directly over a joint, like in a hinge. Sort of like a reversing section on track where they tell you to stagger the joints......not directly across from one another. What You would do, is add an X section to bridge part 4 and 2 or two X section per part. Then You would reinforce the bottom deck with full length I- beams for the deck as I also suggested in My PM. Don't over think this.....It's not that hard. Take Care! Frank Frank, thanks for that reply. As you know, I overthink everything. I had considered what you pointed out about stress on the x-sections. That would certainly be true on a real bridge, but stress on an HO scale model??? Rich
zstripe richhotrain What I fail to understand though is why the kit was designed with that 60/40 arrangement. That complicates the insertion of additional center sections. So, I need to further analyze how to pull this off. I invite all comments and suggestions in this regard. Rich, Like I said in My PM.......The X sections are the main vertical stress part of the bridge. The 60/40 arrangement was to offset the stress on the X sections where the girders would meet, instead of having them directly over a joint, like in a hinge. Sort of like a reversing section on track where they tell you to stagger the joints......not directly across from one another. What You would do, is add an X section to bridge part 4 and 2 or two X section per part. Then You would reinforce the bottom deck with full length I- beams for the deck as I also suggested in My PM. Don't over think this.....It's not that hard. Take Care! Frank
richhotrain What I fail to understand though is why the kit was designed with that 60/40 arrangement. That complicates the insertion of additional center sections. So, I need to further analyze how to pull this off. I invite all comments and suggestions in this regard.
Like I said in My PM.......The X sections are the main vertical stress part of the bridge. The 60/40 arrangement was to offset the stress on the X sections where the girders would meet, instead of having them directly over a joint, like in a hinge. Sort of like a reversing section on track where they tell you to stagger the joints......not directly across from one another.
What You would do, is add an X section to bridge part 4 and 2 or two X section per part. Then You would reinforce the bottom deck with full length I- beams for the deck as I also suggested in My PM. Don't over think this.....It's not that hard.
Frank, thanks for that reply. As you know, I overthink everything.
I had considered what you pointed out about stress on the x-sections. That would certainly be true on a real bridge, but stress on an HO scale model???