Tracklaying Questions

[wazzou]

Beautiful work Dave - your bridge has the cap running along the top edge of the ties.  Does this come with the kit or have you used some material to create that?

Tim

These are called guard timbers and are used to keep the ties in alignment and from moving about over time.  They are more often than not 4x8-16' or 20'.

[BCR 570]

Thank you all for your replies.  My Micro Engineering bridge flex track has come home from the hobby shop and it looks good.  The instructions have alerted me to the need to paint and weather the track prior to gluing it to the bridge, so I will have to consider how I wish to paint and weather it, and which adhesive to use to glue it to my FUD bridge.

Tim

[BCR 570]

With my mainline turnouts now powered up and operational, I have finished all of the electrical work underneath the upper deck above the Pine River bridge:




This temporary wood span with Code 40 track has served the layout for several years while electrical work went on above.  Now that is complete, and I will be able to switch back to the 3D printed model of the bridge:




I have purchased the Micro Engineering Code 55 bridge flex track for this project, upon suggestion from others have acquired some canopy glue for adhering the track to the bridge.  The advice I have received from others here, which I am most grateful for,  is as follows:

- bend guard rails in at each end but don't allow them to touch
- cut off locating nibs at each end where guard rails bend in
- degrease bottom of guard rails and tops of ties with Bestine
- glue guard rails down with thick CA; use Accelerator to improve adhesion and strength
- no rail joiners for guard rails; leave small gap between guard rails (ie. paper spacer)
- use Atlas Code 55 rail joiners at each end rather than ME ones

I would love to get the track assembled and in place on the bridge in time for next weekend's layout tours, but I suspect that there is more work here than I have time for this week.  We'll see.


Tim

[Scottl]

Tim,

That is the strategy I used for guard rails on my bridge and it has stood the test of time. 

The bridge is fantastic- was it a single FUD casting or built up from components?  I'm very interested to learn how that went.

[BCR 570]

Hi Scott:

The truss work is made up of many component FUD pieces.  It was built exactly to the railway's original blueprints and is correct in every detail.  The friend who engineered the parts for me wanted to assemble it himself as it was the second bridge he had produced, and wanted to see how the parts went together, so unfortunately I cannot comment on the assembly phase.

The abutments and piers are single pieces, and are hollow, which is interesting in that the two tall H-shaped piers could never have been injection-molded that way.

This was likely the best solution for this span, as I simply would not have had the time to scratch-build it myself.  I will be scratch-building the other major bridge on the layout, and have not gotten around to that yet.  For those of us who are working and trying to build a layout in what little spare time we have, I have learned that there are some projects for which an investment in time works well, and there are other projects for which an investment in money is the best solution.  This was one of the latter.

I should also point out that the bridge was produced some ten years ago, and there have been considerable improvements in access to etching and 3D printing technologies; if I were doing it again, I would investigate a mix of those approaches as you have done.

Time to cut some track!


Tim

[nkalanaga]

Today it would probably be possible to print an entire truss span as one piece, although I hate to think of the complexity of the artwork.

That might be a niche for a new company.  Most railroad bridges were more or less "standard", in that the basic parts were of the same types, although different sizes and shapes.  It should be possible to program a graphics computer to generate a bridge of almost any length or weight capacity, create the 3-D file, and have it printed.  Send the company your needs, and probably fill out a form of design features, based on the standards of various railroads, and in a few weeks, get the completed span, ready to paint.

[Scottl]

Thanks Tim, that is very interesting- glad it worked out.  It looks great.

[BCR 570]

I have made a good start on preparing the flex track for my Pine River bridge.  I began by assembling a short test section:




I encountered no problems with affixing the guard timbers and guard rails.  This short section will be used to test for painting and weathering techniques.


I noticed that the outer ends of the ties were quite uneven and was not sure how to align the guard timbers.  I thought that they would likely look best if they were at least parallel with the outer rails, so I made a styrene jig to sit on the ties between the outer rails and the guard timbers.  This worked well as long as I removed the jig quickly to avoid it being glued in place:




The guard rails were easy to install.  I think that the manufacturer intended for these to be located between the locating nibs and the tie plates ie. very close to the outer rails, but on the British Columbia Railway's bridges the guard rails were much farther in toward the centre of the track.  I located the guard rails inside the locating nibs and was able to achieve an appearance which resembles my prototype:




A little bit of work each evening resulted in all three sections of track assembled by the end of the week:




Next up is bending and installation of of the end guard rails, assembly of the refuge bays, installation of feeder wires, painting and weathering.


Tim

[Van Horne]

Better get moving, Tim!  We are expecting to see all that finished by Wednesday evening!

Dave Hunter

[BCR 570]

Hi Dave:

Good luck.  I was unprepared for how much work this is.  I am probably looking at a whole afternoon tomorrow getting the refuge bays assembled, and hopefully the feeder wires attached.  Then I will have to wait for some decent weather to paint the track outside on the balcony.

Tim

[peteski]

Tim,
I hope that you saw https://www.therailwire.net/forum/index.php?topic=40497.msg500863#msg500863

[BCR 570]

Yes thank you; I knew that would happen so I scanned some prototype photos just in case.

Tim

[robert3985]

Uhhhh....I hate to say this, but it appears you've cemented the guardrails on the wrong side of the ME bridge guard rail nubs.  They should be closer to the main rails, which measurement the nubs give you, but on the other side of the nubs.

Photo (1) - Here's ME C70 bridge track w/C55 guardrails on an improved Kato bridge (on the left) compared to a stock, unimproved Kato bridge:


Photo (2) - ME C55 bridge track w/C40 guardrails on improved Vollmer bridges:


Looking at my prototype photos of the twin Warren Truss bridges at Taggarts Utah on the double-tracked UP mainline, it appears that there is a two-stage "closeness" of the guardrails to the main rails, with them being close most of the bridge length, but tapering before they leave the bridge structure to about what you have...then more sharply tapering and coming together after they are well out of the bridge structure.  Here's a not-so-sharp drone photo of what I'm talking about...

Photo (3) - Blurry drone shot of Taggarts west-bound Warren Truss bridge's guard rail configuration:


The adjacent bridge has the more conventional guardrail arrangement with no long taper like the west bound track.

Could be I'm up in the night about your guardrails, but they struck me as not close enough to the main rails, but further looking at what I'm modeling tells me that there's a possibility that your prototype could indeed have a different guardrail arrangement than what I've seen here in Utah/Wyoming...

Just sayin'... 

Cheerio!
Bob Gilmore

[Scottl]

His spacing is prototypical in some cases.  I can't speak for the particular bridge he is building, but there are many bridges in BC with that  guardrail spacing.

[BCR 570]

Uhhhh....I hate to say this, but it appears you've cemented the guardrails on the wrong side of the ME bridge guard rail nubs.  They should be closer to the main rails, which measurement the nubs give you, but on the other side of the nubs.

I am afraid that you have not read my earlier post:

I think that the manufacturer intended for these to be located between the locating nibs and the tie plates ie. very close to the outer rails, but on the British Columbia Railway's bridges the guard rails were much farther in toward the centre of the track.  I located the guard rails inside the locating nibs and was able to achieve an appearance which resembles my prototype:

His spacing is prototypical in some cases.  I can't speak for the particular bridge he is building, but there are many bridges in BC with that  guardrail spacing.

Yes indeed, like the very ones I am modelling!

Pine River bridge




Highway 97 overpass

there's a possibility that your prototype could indeed have a different guardrail arrangement than what I've seen here in Utah/Wyoming...

Yes, there appears to be quite a variety with respect to prototype practice.  The narrower arrangement seems to be the common practice on the BCR.  I am just grateful that the design of the ME track allowed me to use the nubs in a way other than intended to achieve the look I need.


Tim