Large Scale Central

Trestles in a ladder system

Track and Trestles
#1

Ok So I am no where near ready to start laying track but I am dreaming about a layout. The wife has deeded me a 50 X 12 foot area in the side yard. I wont bore you with all the details but it will have two separate loops one over the other with one crossing and one area to switch between loops to make one long double loop. I am hoping to make the ladder using 2 1/2 X 3/4 wide vinyl trim. I wanted to stay at or below 1.5% grade. I accomplished that in my design and came up with the crossing point being 12 1/2" separation from top of rail to top of rail. Figuring if I had to leave the 2 1/2 inch ladder material in place it would give me a 10" clearance. I model in F scale with and the loco I am building now will be less than 8" tall. My corner radius are all 4’plus (8’ dia.).

I probably should mention that I am not planning on having this elevated to far off the ground as I have plans to have paths cross it by making small steps/bridges to walk over the track (tunnels for the train). Where the crossing occurs, the lower track will be at ground level with the bottom of the vinyl on the ground and crushed rock brought up to the top of the Vinyl. Then the ladder will rise to the max height of 12 1/2".

Here are a few questions. Is 10" of clearance going to be enough to allow others to play? No giants will be able to run but any smaller equipment should make it with the corners and clearance, right? Oh I doubt it matters but there will be no track power, sorry none battery guys.

Now for the main questions. How does one construct trestles in the ladder system? I have plans for one that I would like to be about 3’ long for the crossing. It will cross a canyon. Do you break the ladder and then use the trestle to support the track? If so what do you use for a base for the trestle to keep it from heaving? My thoughts would be to dig two holes with a post hole digger down 30" (that’s supposedly frost line though I have never seen it that deep and I do excavating work for a living) and pour two concrete pillars to ground level with some bent over rebar sticking up about an inch or so. Then pour on top of that (it would be one monolithic pour but for explanation purposes) a 2 1/2" thick (thickness of the vinyl) slab wide enough to catch the bottom of the bents and 3’ long. This would be the base I could work off of for the trestle. I would also pour in two bolts on each side that the ladder would anchor too. This would be the starting point for the whole system. Does this sound reasonable? Am I trying to reinvent the wheel? Overkill? Not enough? would be easy to do and seems like a rock solid starting point.

Suggestions and links appreciated.

Devon

#2

I think that the heavy pilings for the bridge may be overkill. A simple wood bridge, built from cedar or redwood really works like the real thing, and would hold up the line easy. I have seen scale wooden bridges span 6 ft and could be extended. Use the KISS principal. Using the “Ladder” system, is bridges in its self, each section between posts is really a small bridge.

#3

My corner radius are all 4’plus (8’ dia.).

Go bigger if you can! 10’ would be better!

#4

I think your trestle idea would work, but like Dave said it is real overkill. I just used cedar to make my trestles and they seem to work fine.


On some parts, I used some painted foamed PVC or rock for bases; I should have done that everywhere as the cedar is starting to rot where it touches the ground.

#5

Dave Taylor said:

I think that the heavy pilings for the bridge may be overkill. A simple wood bridge, built from cedar or redwood really works like the real thing, and would hold up the line easy. I have seen scale wooden bridges span 6 ft and could be extended. Use the KISS principal. Using the “Ladder” system, is bridges in its self, each section between posts is really a small bridge.

Oops Dave,

No the actual bridge pilings will be scale. I was simply talking about a pad to land the bents on. The pad would have two cement pilings extend below frost line with a flat cement cap. And this still may be over kill. What you see above ground will be a prototypical five pile open frame trestle.

I might be over thinking it but I was thinking that the trestle would be prone to move more than the ladder it is connected too. So I was thinking the pad would sever as a anchor point to land the trestle in that would rigidly anchor the trestle to a big ol’ piece of concrete that extends below the frost line. I have seen a similar thing done for a brick wall. The sunk those cardboard tubes below frost line and then framed up a slab and made one poor that served as a base to start the brick wall.

Now this is no brick wall so I might be just nuts. But I figured at the end of the day the slab would serve to land the bents and I could epoxy them to the slab and also use the slab as a starting point for the trestle.

But I also have no desire to reinvent the wheel. These are the metal ramblings of someone who has no clue. :slight_smile:

#6

Sean McGillicuddy said:

My corner radius are all 4’plus (8’ dia.).

Go bigger if you can! 10’ would be better!

Sean I am limited by that 12’ width (house and a fence). When I say 8’ dia. that is a minimum number that I won’t allow myself to go below. This is a design control figure to see what I can do with the space given. With the double loop I have two sets of track that need minimum separation. All that said the corners will be as big as the space lets me put in, in reality. My personal equipment I believe will manage the tight corners fine, little 2-6-0s and 30’ scale cars. But I would like others to run also so I will squeeze as much out of it as I can. The only exception to this rule will be my Wye track that has a little short section of curve that might be below the 4’ radius but only for few inches.

#7

Nice photo Bruce.

I think you are over thinking it. Trestles are like the ladder bed system. You could just put your trestle bents on a bed of gravel. Once your bents are all tied together with cross bracing they will be pretty solid just like the real deal.
I have 4 trestle bridges and one pony truss with a center trestle type bracing and they all just sit on the rocks, gravel and the ground. After several years I have had frost heave just once on the pony truss. Of course Winters in Idaho are colder than here on Cape Cod but don’t over think it.

Don’t forget how hot it can get in the Summer so you will want to leave a bit of wiggle in your track to compensate for the expansion and contraction.

10" height sounds pretty good, My tallest equipment like the bachmann 38 ton shay with balloon stack is 8" tall. Do keep in mind that you may limit the size of your equipment now but as your interests grow so will your trains. I never thought I would be interested in modern passenger cars but guess what now I am and they would look silly going around some of my tighter curves.

Happy RRing

#8

Todd Haskins said:

Nice photo Bruce.

I think you are over thinking it. Trestles are like the ladder bed system. You could just put your trestle bents on a bed of gravel. Once your bents are all tied together with cross bracing they will be pretty solid just like the real deal.
I have 4 trestle bridges and one pony truss with a center trestle type bracing and they all just sit on the rocks, gravel and the ground. After several years I have had frost heave just once on the pony truss. Of course Winters in Idaho are colder than here on Cape Cod but don’t over think it.

Don’t forget how hot it can get in the Summer so you will want to leave a bit of wiggle in your track to compensate for the expansion and contraction.

10" height sounds pretty good, My tallest equipment like the bachmann 38 ton shay with balloon stack is 8" tall. Do keep in mind that you may limit the size of your equipment now but as your interests grow so will your trains. I never thought I would be interested in modern passenger cars but guess what now I am and they would look silly going around some of my tighter curves.

Happy RRing

Thanks Todd,
I will scrap the giant piece of concrete then and just land them on maybe pavers or whatever. Frost heaving I actually don’t think will be an issue. I only have about maybe a foot of topsoil then it is a couple hundred feet of gravel. My soil does not hold water. But I have never paid any attention on a fine scale like our railroad.

Here is a great drawing I found. This is exactly how I envision my trestle looking.

http://3.bp.blogspot.com/-JeJpHked-x0/UYkR6bbfBZI/AAAAAAAADms/eDYnlnUO5nY/s1600/3.jpg

#9

This is what I built to access my Mtn. Division.

And the curved track on a straight bridge.

All set on brick bases.

#10

Dave Taylor said:

This is what I built to access my Mtn. Division.

And the curved track on a straight bridge.

All set on brick bases.

Dave how did you make your supports for where there are no bents. This is something I will have to do to get the train under it. Would you mind sharing a close up of that detail?

#11

Devon, frost heave in our neck o’ the woods is seldom a problem, though you might have a micro issue on your property that will make a liar out of me. Unless you have rocks popping out of the ground each spring, I wouldn’t worry about it. The Rathdrum Prairie is almost all sandy loam.

For my trestle (long gone, due to ROW changes), I used a 1 X 6 cedar board, the length of the trestle as its base, then used 2 X cedar, cut to size to support the bases of the bents at various heights, as though they were resting on rock substrate. When installed, the cedar base rested on 2 inches of gravel for drainage, then I backfilled basalt gravel on top as though it was talus. I though it looked pretty good.

#12

Steve Featherkile said:

Devon, frost heave in our neck o’ the woods is seldom a problem, though you might have a micro issue on your property that will make a liar out of me. Unless you have rocks popping out of the ground each spring, I wouldn’t worry about it. The Rathdrum Prairie is almost all sandy loam.

For my trestle (long gone, due to ROW changes), I used a 1 X 6 cedar board, the length of the trestle as its base, then used 2 X cedar, cut to size to support the bases of the bents at various heights, as though they were resting on rock substrate. When installed, the cedar base rested on 2 inches of gravel for drainage, then I backfilled basalt gravel on top as though it was talus. I though it looked pretty good.

Yeah that’s what I figured Steve. I have zero clay and only about a foot if I am lucky of sandy loam. The good old Rathdrum Prairie gravel/rock/sand. I don’t expect a problem.

#13

I did pour a slab for my trestle to rest on. No footings, and the slab is between an inch to 2 inches think with hardware cloth in it to act as small rebar. The trestle just rests on that slab, because things will move a little and I want things to be able to move a little instead of get stressed and break. I understand the desire to over-engineer things so that they won’t fail, but a huge monolith for the trestle sounds like overkill to me. Especially if the day ever comes when you want to change something.

Like Todd said, once all the bits are assembled, the structure becomes very strong and ridged. I built this for a friend of mine, its just sitting on my living room floor for its builder’s photo. Even though it looks a bit delicate, its actually quite strong. It had no complaint holding up 20 some pounds of Aristocraft Pacific.

#14

David Maynard said:

I did pour a slab for my trestle to rest on. No footings, and the slab is between an inch to 2 inches think with hardware cloth in it to act as small rebar. The trestle just rests on that slab, because things will move a little and I want things to be able to move a little instead of get stressed and break. I understand the desire to over-engineer things so that they won’t fail, but a huge monolith for the trestle sounds like overkill to me. Especially if the day ever comes when you want to change something.

Like Todd said, once all the bits are assembled, the structure becomes very strong and ridged. I built this for a friend of mine, its just sitting on my living room floor for its builder’s photo. Even though it looks a bit delicate, its actually quite strong. It had no complaint holding up 20 some pounds of Aristocraft Pacific.

Shannon,

That’s a great shot. I found a real trestle pic that looks like the one you built. That’s just exactly what I want. I can see enough in that shot to piece one together. Thanks to you and everyone else for their input.

#15

Amazing trestles Dave and David.
Mine I like ot keep simple without so much cross bracing. If you have lots of trees on your property Devon a fancy trestle will catch blowing leaves that will need ot be picked out by hand. Just a thought.

If you don’t already have one… get yourself a pin nailer before you begin.

#16

Todd. This will be pretty well protected from the trees. For one it will be right behind the train shed/ bunk house a 7.5’ by 7’ two story building which the bottom floor will be my train shed and the upper section will be a play house for my eventual grandkids (or me when my wife finds out how much I spent to built the RR). Also it faces into instead of against the prevailing wind. But that is a good thought.

I will have a pin nailer soon.

#17

Trestles 101 - Family Garden Trains. http://familygardentrains.com/primer/bridges/trestle/trestle.htm. A good resource.

Still trying to sus out this tablet.

#18

Steve Featherkile said:

Trestles 101 - Family Garden Trains. http://familygardentrains.com/primer/bridges/trestle/trestle.htm. A good resource.

Still trying to sus out this tablet.

You rock Steve,thanks

#19

" The Rathdrum Prairie is almost all sandy loam."

Apparently you’ve never dug a hole in the Rathdrum prairie, Steve.

Or the Spokane Valley. All the rocks left by the Great Ice Age Flood are deposited there.

I wish it was sandy loam. Then I wouldn’t have had to haul in 12 yards of topsoil for my new front yard.

Just sayin’…

#20

OK, do you have frost heave problems, jb?