Question about roadbed, piers, and bridges

[liquidcross]

QUOTE: Originally posted by vsmith
Wholesaletrains.com shows that Atlas sells an HO pier set (ATL80) that used stone piers and is 46 pieces, this includes pieces that support the middle of a snaptrack section and looks far more realistic.

If you chose to, It would not be difficult to add the additional members I mentioned to the underside of the snap track. You would simply be adding a deck under the rail between the piers and would not need any X-members like a wood trestle would need to look right.

That would work...except I'm modeling in N scale. [;)]

What kind of material would I use for the "deck"? Would that just be a flat piece supporting the tracks?

[vsmith]

QUOTE: Originally posted by liquidcross

QUOTE: Originally posted by vsmith
Do you know what piers , bridge kit, etc. you are planning on using? Atlas? stone? steel? wood?

I'd be using Atlas' pier set (#2541) and their Warren truss bridge (#2546). The bridge itself should look fine...I'm more concerned with the look of the long loop of track that'll be up on piers (almost the entire main line).

Wholesaletrains.com shows that Atlas sells an HO pier set (ATL80) that used stone piers and is 46 pieces, this includes pieces that support the middle of a snaptrack section and looks far more realistic.

If you chose to, It would not be difficult to add the additional members I mentioned to the underside of the snap track. You would simply be adding a deck under the rail between the piers and would not need any X-members like a wood trestle would need to look right.

[88gta350]

If I were you I'd forget the trestles and use Woodland scenics risers as someone else mentioned. This is just a long piece of foam that has a gente rise and you can shape it around curves. It would take the place of the trestles. You then build the scenery up around the foam to hide it so the track looks like it's just going up a hill. You can use whatever bridge you like. I believe woodland scenics website is at www.woodlandscenics.com or Walthers also carries it. www.walthers.com

It will give you a much, much more realistic appearance than the cheap atlas trestle suspending the track in mid air.

[liquidcross]

QUOTE: Originally posted by vsmith
Do you know what piers , bridge kit, etc. you are planning on using? Atlas? stone? steel? wood?

I'd be using Atlas' pier set (#2541) and their Warren truss bridge (#2546). The bridge itself should look fine...I'm more concerned with the look of the long loop of track that'll be up on piers (almost the entire main line).

[vsmith]

QUOTE: Originally posted by liquidcross

QUOTE: Originally posted by vsmith
If they dont and your still planning on using the Atlas trestsle piers then a good way to avoid the toytrain look is to add cross members (scale steel beams for example) under the snaptrack sections and add cross bracing to the sides of the peirs like a real bridge. This would allow you to hide the toytrain appearance of the snaptrack.

Forgive me for sounding stupid...but I have no idea what crossmembers and crossbracing would look like. Got a picture anywhere?

Sorry, I cant post photo's, but if your planning on using Atlas snap track (track only woth no plastic roadbed) at the bridge portion stone piers then you should be able to use Atlas girder plate bridges and Atlas Truss bridges at the pass under to span between the peirs. If I remember right the bridges snap into the tops of the piers and the Atlas track snaps into the bridge. this eliminates almost 90% of the problems associated with putting a bridge onto an over and under layout.

If on the other hand your planning on using the peirs that resemble a wood trestles peirs then as I suggested adding cross members and supports will improve the looks. The crossmembers would be the wood beams that support under the track, with snap track these could just be styrene square strips that Evergreen or Plastruct sells, these could simply be cut to fit the space between where the peirs connect to the track and glued with CA to the underside of the snap track. It just needs to be up against the piers, not necessarily connected to them, as the track is self supported. Your trying to "fill" the void under the track where the structure of the bridge would be in reality.

The crossbraces are the pieces of a wood trestle designed to prevent the struscture from swaying under the wieght of a train. there would be X members on the side of the peir spanning from one pier to the other. Almost any RR bidge photos of wooden trestles will show this.

The thing is with a wood trestle you should consider adding additional supports. Instead of one support at each snap connections like the stone pier with Girder bridge would have, a wood bridge would have twice the supports, on at the end and an additional supprt in the middle of the snap track. Wood bridges alway had more supports than steel bridges.

Do you know what piers , bridge kit, etc. you are planning on using? Atlas? stone? steel? wood?

[Jetrock]

eriediamond: No, if you're building wooden piers, don't ballast that part of the track. I assume you're going to cut out that portion of the wood, so, for starters, you won't be able to put cork roadbed there as it will be an inch or three off the :ground." You have two choices here--either leave the space "empty" until you've gotten to the scenery stage, or use those cheesy Atlas or Bachmann train-set trestle pieces (wood or concrete) as place-holders to hold your track off the ground until you're ready to build the bridge. The unsupported track hanging in midair between the piers won't look that weird.

In fact, I'm fairly certain you can get "bridge track" from a number of suppliers--flextrack with more frequent ties, as one sees on a bridge or trestle.

Take a look at the prototype--leaf through some books on trains or if there is a similar trestle near you, go take a look at it to see what the prototype did. Some lines did ballast track on bridges (near my home there is part of a wye that is suspended by a modern concrete bridge over a freeway--the track is ballasted!) but generally they didn't, preferring to attach the track directly to the bridge material.

[liquidcross]

QUOTE: Originally posted by vsmith
If they dont and your still planning on using the Atlas trestsle piers then a good way to avoid the toytrain look is to add cross members (scale steel beams for example) under the snaptrack sections and add cross bracing to the sides of the peirs like a real bridge. This would allow you to hide the toytrain appearance of the snaptrack.

Forgive me for sounding stupid...but I have no idea what crossmembers and crossbracing would look like. Got a picture anywhere?

[vsmith]

QUOTE: Originally posted by Eriediamond

I agree with all the above suggestions but want to add this. your comment about looking weird with cork road bed going over the piers prompts this reply. Yes it would look weird. Atlas piers are designed to snap on to the track it self to support it. If you are after the toy train look, then use the piers as directed by Atlas, they work just fine. But they would look weird also. Have you ever seen real track supported between piers by the rail only?? Regards, Ken

Doesnt Atlas still sell girder and truss bridges designed to work with thier stone peirs and snap track? I remember seeing these on thier publications, they were quite common, arent they? I even remember they had a curved girder bridge for just such an application as described. Have they stopped making these?

If they dont and your still planning on using the Atlas trestsle piers then a good way to avoid the toytrain look is to add cross members (scale steel beams for example) under the snaptrack sections and add cross bracing to the sides of the peirs like a real bridge. This would allow you to hide the toytrain appearance of the snaptrack.

[Eriediamond]

I agree with all the above suggestions but want to add this. your comment about looking weird with cork road bed going over the piers prompts this reply. Yes it would look weird. Atlas piers are designed to snap on to the track it self to support it. If you are after the toy train look, then use the piers as directed by Atlas, they work just fine. But they would look weird also. Have you ever seen real track supported between piers by the rail only?? Regards, Ken

[liquidcross]

I plan to use piers; that's what the original layout plan specifies, so I figured I'd trust their judgment. I just think it'll look kinda weird if there's ballasted cork roadbed going up above the rest of the ground (on the piers)...or does track on piers not use that kind of roadbed or ballast?

[Anonymous]

In the upper right where the "loop" crosses the other three tracks, you have a number of options.

It looks like the curve continues from the top over at least the first track. It is possible to have curved track on a bridge, but beware the clearances!! You will need to make the bridge wider than normal to handle the curve and car/loco overhang, especially if it is a "through" type bridge - that is a bridge with sides above the track. A "deck" type bridge has no sides, but will still need to wider than normal to accomodate the curve. In this case, you stop your cork at the point were the bridge starts.

If you don't want to worry too much about proper bridge track with the closely spaced ties, you can do a ballasted deck bridge. You would build a bridge like a concrete culvert (for instance) and run the track right across, including cork, ballast, and so on.

As for the slope leading up to the bridge... you can put it on piers if you want, or you can use something like Woodland Scenics risers to make a grade. They come in 2, 3 and 4% I think. Go for as shallow a grade as possible. You can fill in with landscaping, or run a retaining wall along both sides, or whatever to disguise the riser.

If you want to try something different, try putting this track in a cut or tunnel UNDER the other tracks. If you plan to operate, reaching over/around a bridge (or three) can be a pain, and often means wrecked scenery or other stuff. If you try a tunnel, you can start going down on the outside loop just after it passes the yard, and come up on the inside loop just after the last crossing (assuming clockwise running). That way your yard and the siding are at the same level, and the "mainline" makes a gradual decent and climb - easy on the engine(s).

Anyway, just some thoughts. Hope it helps.

Andrew

[liquidcross]

Hey folks. I'm planning to build the following layout (from Atlas):



The section in the upper right will be a bridge, but being an amateur, I'm not sure how to properly lay roadbed for it. I know you use cork or "instant roadbed" on the table itself, but what should I do for the track that's going up on piers to the bridge? Do I still use roadbed and ballast it, or is there something else I should for semi-realism?

Thanks in advance! :D