building trestles

[Anonymous]

Should trestles be built before or after scenery?

[Big_Boy_4005]

Tough call, it depends on a number of factors.

Type of trestle wood or steel?
Straight or curved?
Equal height bents?
Crossing water or land?

If possible, build the trestle first, and place the footings in the rough terrain. Get the fit correct, remove it to scenic under it, then do the final install. A water crossing requires that the trestle be in place at the time of the pour.

I actually built a curved wooden trestle in place on the layout once. A regular feat of civil engineering.

[nfmisso]

yes

[Anonymous]

Im building a wooden trestle only about 1ft long and 1ft deep. The valley it crosses has fairly steep slopes. Im thinking about building the tresles without scenery, on solid wood then build the slopes around it. hopefully this will help to avoid any problems.
Thanks for the opinions.

[Big_Boy_4005]

Your plan sounds just fine. I would say that is the traditional approach.

[cacole]

On our club layout we built the first 6-foot long curved trestle with equal-length bents set onto the plywood base, and then formed the scenery afterward.

When it was decided to build a second trestle in the same area, it soon became apparent that it was much easier to cut out all of the scenery to get to a solid base for the trestle, and then rebuild the scenery.

[ham99]

I put the trestle in place first, and then added the scenery. The foam making up the rough shape was in place first, then the trestle, then the Sculptamold, next the ground cover, and last was the water pour. It was kind of close quarters [N scale] for shaping the Sculptamold under the trestle, but I shaped it with a 1/8" dowel and it turned out fine. I blew the ground cover [WS turf] into place with an ear syringe. The alcohol and glue/water went in with a eye dropper.

[claycts]

QUOTE: Originally posted by ham99

I put the trestle in place first, and then added the scenery. The foam making up the rough shape was in place first, then the trestle, then the Sculptamold, next the ground cover, and last was the water pour. It was kind of close quarters [N scale] for shaping the Sculptamold under the trestle, but I shaped it with a 1/8" dowel and it turned out fine. I blew the ground cover [WS turf] into place with an ear syringe. The alcohol and glue/water went in with a eye dropper.

Text book approach.

[Anonymous]

I built mine as I did the scenery. I formed up footings with balsa and poured them with plaster just like concrete. My trestle bent bases were installed with about a 1/2" of the pilings down in the plaster. Stringers and some extra support held them while the plaster set up. Added the ground cover before I laid the ties and track to be able to get it down aroung the bents good. Worked pretty good.

[West Coast S]

Guess i've got my work cut out for for me, I require one six feet long! I'm leaning towards building it away from the benchwork so I can scenic between the pilings.


Dave

[howmus]

QUOTE: Originally posted by Tweet469

I built mine as I did the scenery. I formed up footings with balsa and poured them with plaster just like concrete. My trestle bent bases were installed with about a 1/2" of the pilings down in the plaster. Stringers and some extra support held them while the plaster set up. Added the ground cover before I laid the ties and track to be able to get it down aroung the bents good. Worked pretty good.

When I built a trestle about 20 years ago. I too did both at the same time. I made a jig for building the wooden trestle supports so that each was the same. I then cut and fit each into the scenery as the entire scene was built. They are dependent on each other so I made changes as each part came together.

[doctorwayne]

I built one multi-span (3 deck girders, 1 through truss, and 1 more deck girder) over an area representing the point where a medium-size river empties into a lake. The riverbed is plywood and it extends out just past the ends of the bridge and is about 17' (HO) below the railhead. I installed the roadbed (3/4" plywood) right across the area, put down some cork and flex track, and then ran trains. When it came time to build the bridge, I used a large piece of paper to make a "rubbing" of the rails in the area the bridge was to span, and then cut out the track and roadbed in that area. The bridge was built up using the rubbing as a template and consists of a 30' ME deck girder, a 50' ME deck girder, an Atlas through girder cut apart and made into a deck girder, a CV through truss, and another modified Atlas through girder, all laid out on a very gentle ess curve and a slight grade. I cast the piers and abutments in Durabond 90 patching plaster, keeping in mind the change in elevation and the varying depths of the individual spans, and used the assembled bridge to locate these parts on the river bed. The scenery was then extended down onto the riverbed so that the abutments on either end are set back from the water's edge. The finished span is over 4 1/2' long and the track and bridges are removeable from the piers. I've just finished the trees on the riverbank and hope to do the water soon. The whole job was very enjoyable and the results, in my opinion, look pretty good.
On the other side of the layout, I built two bridges, each one about 4' long and each on a fairly severe grade. The first one is part of the end of a 30" radius horseshoe curve and is built across an irregular-sided valley with a narrow river at the bottom. The riverbottom is plywood and the valley walls are Durabond on wire screen. The bridge was built using a rubbing of the roadbed as a template and consists of 4 ME tall viaduct towers and girders and 5 various ME span girders.. The completed bridge was held over the site and each of the tower legs was trimmed to suit the terrain. When everything seemed to fit I used the bridge to locate the tower footings. I used Durabond to cast footings (four per tower) and then carved the bottoms to suit the varying terrain. I installed 1/32" piano wire pins in each footing, (I want the bridge to be removeable) and then installed the footings on or in the valley floor. The abutments at either end were cast in place. This area has not been scenicked beyond the basic landforms but I hope to disguise the unprototypical (I think) unequal length legs on the towers with underbrush and trees.
The third bridge is on an almost imperceptable ess curve and consists of three ME tall viaduct towers connected to the abutments by 50' ME deck girders and to each other by Atlas deck trusses. The abutments and footings are .060" styrene, stacked together and filed to shape for the footings, and .060" styrene assembled as sides and tops,etc. for the abutments. The problem here was similar to the previous bridge with the added treat that the valley not only sloped down from either side but also sloped down from back to front. Again, the tower legs are uneven at the bottoms and will be hidden with trees and bushes.
All of the bridges actually look pretty good and they are all very solid and yet still removeable. However, my advice is to plan out the bridge thoroughly, not only as to where it will be, but also right down to the dimensions of whatever combination of components you plan to use. Use this information to locate level and solid support in the areas where it will be required and then add the landforms around or over these supports. Alternately, if you build the bridge to be removeable or if you have adequate clearance around it, you can build the bridge first and add the scenery later. I'm sorry to have gone on at such length, but I wanted to emphasize that the first bridge was fun to build; the other two were exasperating because I didn't plan them thoroughly. I hope this is of some assistance.

[selector]

BTW, one of our master trestle builders is squirreled away as we speak. UKGuy has been quiet for about a week now, and I'm pretty sure he is pulling late nights trying to get the impresive Kinsol Trestle built. I don't know if he is ever going to come up for air, but if he reads here, he may help you out.

[Anonymous]

Thanks all. I have built 5 trestles so far and now I want to scratch build everything. I also built two tunnel portals and a hunting lodge. Thanks for the info

[ukguy]

Thanks for the compliment my friend, although it may over estimate me. In my limited experience I would concur with bigboy and others in that: construct the trestle first as per the general area, remove and add scenery, replace and complete scenery. Although I must add that this is not a given and circumstances may demand a different approach, a good plan of attack is the best first step with all the forseeable problems remedeed in advance.

Let us know how it goes.

Have fun & be safe.
Karl.

(Kinsol has not yet been started Crandell, but as soon as I am able it will be the first thing that I will be working on.)

[claycts]

On this subject all I have to say is "Thank God for CADD" if it works on screen and you build it like the drawing it should fit. In englis, I will build the 5 for my layout on the bench and then do the scenery.
Great input from all.

[ukguy]

Hope it all goes according to plan George.

Have fun & be safe,
Karl.

[claycts]

QUOTE: Originally posted by ukguy

Hope it all goes according to plan George.

Have fun & be safe,
Karl.

That would be a first, Thank you.
Oh the pictures I spoke of http://www.leatherique.net/ho_layout.htm

[jwar]

Man the timing of this one is on target, building the Keddie wye as we speak.

Doctorwayne, uneven bent supports are typical in steap mountain ranges, ie, the keddie and another on the Rio Grande( forget its name). Also you gave me some good ideas and glad your reply was long, thanks.

I hope Im on target and this is the plan, so critque if you wish. [8D] Two 38 in bridges curving into the wye, both are steel tressels. Im making elavated supports for the bent concreat supports, building the bridge with a hidden plywood spline, will be removable, as well as the bents after the top (bridge spans) removed, as latter on I want to set up a log landing operation in the valley.

Being Im into screen and plaster Ill hot glue my screen in after the bridge is removed.

Thanks to all above, have a great day....John