Viaduct Parts

[John]

A first test print from a file set off thingiverse --  https://www.thingiverse.com/thing:5389817

The author designed the files after the Micro Engineering Tall Viaduct but he made the small span 100mm vice 80 and the long 180 vice 150 .. he also designed it as double track - so all the piers are wide ..

I split the decks back into single width - and will try to add the bolt pattern to the sides .. also need to put X bracing on the ends ..

[samusi01]

Interesting. Purely by chance, was out droning this afternoon for a future project and grabbed a series of pictures of a local bridge. Do you intend to add in any intermediate cross-bracing?

Bonus pier shot:

[John]

For now - this is as far as I've gotten .. The rivet pattern needs more work - and in Tinkercad the file size grows rapidly when adding them ..

Looking at your image above - I might try to make the sections smaller, then join them as needed for larger spans .. sort of an erector set ..

[samusi01]

The span I was taking pictures of is (per google earth, at least) around 1,400 feet long and appears to be made of a series of (again, google earth) 78-80 foot long spans which appear to be basically two single track bridges right next to each other using the same piers. It replaced an earlier truss bridge of some sort. I do like your rivet patterns but they do tend to slow things down... note at end of span they are usually doubled. Two more images that may or may not be helpful, one an old NP span up in Missoula:

[TrainCat2]

Using other items in the pic to calculate height, I figure the depth of the girder span to be in line with standard 90ft sections. At 1400ft, most railroads would have used 90ft or 100ft deck girders. Count the number of piers, add 1 and divide 1400 by that to get an accurate length. Usually, RR's would add a few cross bracings (typically 3) between the two girder spans to help keep the spans in alignment but still be flexible for temperature shrinkage and expansion.

[wcfn100]

The rivet pattern needs more work - and in Tinkercad the file size grows rapidly when adding them ..

If your using half spheres for the rivets, try just using cylinders.  They will print fine and reduce the file size.


Jason

[samusi01]

Using other items in the pic to calculate height, I figure the depth of the girder span to be in line with standard 90ft sections. At 1400ft, most railroads would have used 90ft or 100ft deck girders. Count the number of piers, add 1 and divide 1400 by that to get an accurate length.

Interesting. I calculated the length by measuring pier ends; there are two different types of piers, the older cut stone angled end from the predecessor bridge - which I do not have any information about - and the newer intermediate concrete square ones.

Edit: added the other side for comparison. The old vs. new piers better shown here. Interesting detail.

[TrainCat2]

Typical Girder dims for railroad bridges. A bridge engineer gave me a page from his book when I started designing the brass bridges. I can't find that specific one, but I also had another from online. Don't remember where it came from, just that it was in very close correlation to the original that I was provided.

[John]

If your using half spheres for the rivets, try just using cylinders.  They will print fine and reduce the file size.


Jason

That's what I was doing .. thanks for the hint .. will try that on the next print

[John]

Typical Girder dims for railroad bridges. A bridge engineer gave me a page from his book when I started designing the brass bridges. I can't find that specific one, but I also had another from online. Don't remember where it came from, just that it was in very close correlation to the original that I was provided.

Is the depth value the "height" from bottom to top of girder?

[John]

If your using half spheres for the rivets, try just using cylinders.  They will print fine and reduce the file size.


Jason

Ok .. created a copy of my rivet master using the cylinder vice sphere ..

The sphere was 847KB and the cylinder was 49kb (blue one) -- quite a difference .. next up is to print a sample ..

[wcfn100]

Ok .. created a copy of my rivet master using the cylinder vice sphere ..

The sphere was 847KB and the cylinder was 49kb (blue one) -- quite a difference .. next up is to print a sample ..

Tip courtesy of Mark Gasson of Mark4Design way back in the day.

Jason

[TrainCat2]

Is the depth value the "height" from bottom to top of girder?

Yes, just the girder plate. You need to add the top & bottom cover plates,

[Jesse6669]

Another tip is to group them and create a custom shape in "Your creations" of the assembly, then just apply those.

Ok .. created a copy of my rivet master using the cylinder vice sphere ..

The sphere was 847KB and the cylinder was 49kb (blue one) -- quite a difference .. next up is to print a sample ..

[John]

Micro Engineering vs M&O Engineering

The test print came out rather well .. thanks for the hint about the rivets .. It compares well against the ME girder ..  also added the rivets on the top based on BoB's images