?:Atlas Through Truss Bridge - End Abutments

[DigitalGriffin]

What are people using for end abutments on the through track bridge?  The Atlas model keeps the track bed particularly low which creates issues when used with standard abutments resting lips.

I'm refering to this bridge:

[zstripe]

Did You look at any Chooch offerings? They are cast resin, can be cut with a fine tooth wood saw or hacksaw. I use an Xacto wood saw,makes a faster cut then the metal saw. If interested:

http://www.choochenterprises.com/8440.html

The resting lip is roughly a 1/2''. Also other styles. They come Grey in color.

Take Care! 

Frank

BTW: The Atlas one's in the pic' are Piers not Abutments.

http://www.choochenterprises.com/HOpiers.html

 

[peahrens]

I can't comment specifically on the Atlas but will add to what Frank suggests. 

I have a combo truss / girder bridge pair, on a grade.  I happened to pick Central Valley kits. 

As seen in the photo, I needed two abutments at the ends plus a pier in the middle.  I don't think I could have found abutments and piers in a style (stone type) I would like plus have all the dimensions to perfectly fit my needs of height, the different heights from bridge shoe to roadbed top, the bridge roadbed thickness difference from the cork roadbed on the approaches, etc.

So, as Frank suggests, check out the Chooch offerings and others.  Their website shows the key dimensions including height, drop from the top to the bridge shoe shelf, etc.  I just bought ones that were a bit too tall and cut them to the needed overall height.  Then it is often also necessary to shim the bridge shoes and/or to cut (e.g., Dremel) the shelf a bit lower.

The good news is you can use the bridges and abutments / piers you like and modify to fit.  Of course, the scratch builders just make exactly what they need.'

 

[doctorwayne]

I don't have the Atlas through truss bridge, but I do have a lot of bridges, including Atlas deck trusses and Atlas through girders built as deck girders, along with Micro Engineering parts and a Central Valley through truss.  
I cast my own piers and abutments to suit the bridges used and the surrounding terrain...

There's an illustrated how-to HERE

Wayne

[DigitalGriffin]

Thanks guys,

Looking at your bridges I see the problem.  The Atlas bridge track lies directly on the bridge girders and stringers.  Your bridges appear to rest the track ontop an additional plate girder elevating the track enough to go over the upper lip.

So I'm going to have to either:

1) cut down the chooch abutment I have or

2) elevate the track, or

3) add very tall bridge shoes of some sort to the bottom of the bridge to the abutment lip.

decisions decisions.

 

 

[tomikawaTT]

For one end of the truss, rocker-type bridge shoes are rather tall to begin with.

For the other end, you can build up the supporting lip with a layer of anything that can simulate poured-in-place concrete.  The historical fact is, this is the second bridge at this site, so the abutment had to be modified to deal with the changed geometry.

Chuck (Modeling Central Japan in September, 1964 - with lots of bridges)

[doctorwayne]

DigitalGriffin

Thanks guys,

Looking at your bridges I see the problem.  The Atlas bridge track lies directly on the bridge girders and stringers.  Your bridges appear to rest the track ontop an additional plate girder elevating the track enough to go over the upper lip.

So I'm going to have to either:

1) cut down the chooch abutment I have or

2) elevate the track, or

3) add very tall bridge shoes of some sort to the bottom of the bridge to the abutment lip.

decisions decisions.

It wasn't unusual for the real railroads to alter abutments and piers as the situation changed.
This example shows a top course of stone which may have been a later addition to increase clearance for the road over which it passes.

I'd guess the the set-back layer of concrete atop that stone might have, at a later date, served the same purpose, but it could also have been done if the roadbed in the general area on either side of the span had been re-surfaced to take out a sag in the line.

This example shows a similar situation...

...but I'm uncertain as to what the bridge might have looked like in an earlier time.  The thick concrete top on the mid-stream pier to the right (and a thinner one atop the pier to the left of that) suggest that the steel portions of this bridge may have replaced an earlier, lighter-duty bridge of a different design. 

Alternately, you could do what the prototype did here...

...and simply build a new one beside the troublesome piers. 

Wayne

[Heartland Division CB&Q]

Wayne .... You provided a lot of useful information and suggestions.

I made most of my abutments and piers out of wood for various manufacturers of bridge spans.