Building a girder bridge - part 1

This post started out being called "Modifying an Atlas girder bridge" but as you will see it became more of a scratch building project using a couple parts cut from an old Atlas girder bridge.  I am going to need a single track bridge for the AsiaNrail line to pass over the 3 Ntrak lines.  It is also going to need to be wide enough to allow for the track to curve just a bit.

I had several of the old Atlas pony girder bridge sections that were saved from the old module and they are just the right length.  They have nice detail on the outer girder sides but I wanted the bridge to have an open deck and because of the curve I did not think the trains could clear the girders if they were above the track.

Looking for ideas on the Internet I found this photo on RailPictures.Net and realized I had what I was looking for.  There would be clearance to allow for the girders to be under the tracks.  I could cut the detailed girders off from the deck part of the Atlas bridge and use them.  

After cutting through the deck along the edge where the girders are with a razor saw and sanding that area of the girders smooth, I cut 2 sections of .080 x .080 styrene strip to a length equal to the bridge girders.  Then I attached these along that same edge with Plastic Weld.

Next I cut 2 sections of .060 styrene angle to the same length as the bridge girders.  Then I placed a section of .156 I beam material between the square strip and the angle to use a spacer as shown here.  Small amounts of Plastic Weld were used to attach the angle in place.

Because the track that will be on this bridge will have a slight curve to it so I wanted the bridge to be wide enough to allow for that.  I settled on a width of 20 scale feet and cut up 15 sections of the I beam material to this length with my "Chopper".

The bridge girders are 65 scale feet long.  I had made 15 marks 4 feet apart along the L channel on both bridge girders.  Laid out on my metal plate & magnets building jig the I beams can easily be inserted into the channel between the channel on the bridge girders created by the .080 x .080 styrene strip and the L channel.  Yes, those are hacksaw blades used to square up the ends.

After the Plastic weld was set on all those joints, this ends up being a sturdy little structure.  Here is the model bridge sitting on some magnetic bridge abutments. :)




I then added a styrene channel on each end and cut two strips 3 scale feet wide of V groove siding across the board pattern to simulate the walkways.  They cover the top of each bridge girder and .080 x .080 styrene strip and overhang the girders just a little

So far everything I've done with this bridge was from materials I had on hand.  The materials list so far:

• Atlas girder bridge, P/N 2548 (salvaged)
• Evergreen square .080 x .080 styrene strip, P/N 164
• Evergreen .156 I beam strip, P/N 275
• Evergreen .156 channel strip, P/N 265
• Evergreen .060 angle strip, P/N 291
• Evergreen .040 V-groove siding, .060 spacing, P/N 4060

I'll still need to put some hand rails and find the appropriate paint color but it's Sunday and the hobby shop is closed.  I'll also want to re-stock the styrene items I used up so maybe tomorrow I'll try the hobby shop and continue on this project.

Progress report for November 9, 2012

Lately I've been doing some tweaking on the blog itself.  I had noticed that the text in some of the older posts did not line up right with the photos the way they did when they were first posted so I've been going through and fixing some of that then checking it with Explorer, Firefox, and Chrome browsers.  I've also started to put labels in more of the posts and may add a labels gadget to the blog in the future.

But I've also been doing some work on the Hot Springs Junction module project. Seems most of us model railroaders can't wait to start laying cork and track and I'm no different so today I got the cork down for the Ntrak main lines.  I use the old standard Midwest Products N Scale cork roadbed.  On this module I had already done the Ntrak Mountain Division line and the AsiaNrail line.

Nothing special about my method of laying down cork roadbed.  I draw a center line and lay one side down along the line with white glue.  Hold with push pins until it dries. Then lay the other side down the same way.



The next step will be to sand the edges with a sanding block at a shallower angle then the one that is already cut.  One reason I decided to get the cork done now was that these tracks will be down in a cut and I will have better access for the sanding block before the foam terrain is in.  That might be tomorrows project.

Installing profile boards

As this module is going to have terrain above the level of the main bench work, I felt it necessary to install fascia or profile boards above the main bench work.   If the module were being built from scratch as a mountain division module, then the framework of the module could have been designed with this in mind but since this is an old flat module, these will need to be retro fitted.

First step is to cut out the pieces needed and shape the contours.  I used 1/4 inch plywood that was left over from building the light weight sky board for this module.

Before placing the profile boards, I installed a strip of 1/4 inch plywood as showed in this photo.  In some places on taller sections, a brace can be added to help strengthen  and hold the alignment.  Everything is glued with yellow carpenters glue.

In the case of a module like this one, it is important to get the new profile boards on the ends in alignment vertically with the existing module frame.

Later, I'll seal both the insides and outsides of these profiles boards to seal them.  Then the terrain on the inside will be filled out with layers of foam insulation board.

Building the AsiaNrail line

In the past week I did manage to get out to the garage a few times and continue with the bench work phase of this project.  I did install the cork roadbed on the Mountain Division and AsiaNrail lines so I could better finalize the track plan.  I decided on the more conservative single crossover between the lines so that I could allow for a wider radius curve on the AsiaNrail line and for a longer platform siding at the station.  Also started on the fascia on the sides and the front of the module.

This view from the front of the module shows how I placed the piers to support the AsiaNrail line as it diverges from the Ntrak Mountain Division line.




The piers are made from 1/2 inch plywood and attached to the module base with screws and then the AsiaNrail lines sub-road bed is attached with pneumatic cabinet nails.  Of course yellow carpenters glue is also used in both places.

Here's a view from the other direction and the AsiaNrail is seen passing over the Ntrak main lines being represented at this point by three black marker lines.




Also seen here is some of the front fascia board.  I'll talk more about that in the next post.

Testing the track layout

With previous modules or layouts I've used full sized paper printouts of Peco and Micro Engineering turnouts pasted to folder stock to test my track layout. I had quite a few used Peco turnouts and sections of Atlas flex track that had been given to me over the years and decided to use them to try out my track ideas for this module.  Using these I could actually solder the sections together to see how they would all work together.

This view is from the back of the module.  I found that by using a curved turnout to start the stub end siding to the station and could make the curve of the AsiaNrail line a slightly larger radius.

Here the piece of 1/4 inch plywood that will be used for the sub roadbed is temporarily placed so that the cut marks can be made.

This view from the front.  The AsiaNrail sub roadbed has been cut and installed on risers to carry it to the front of the module.

Adding the Ntrak Mountain Division

After all this effort to remove some of the weight from the original module, it is now time to start adding some back.  Remember that old 1/2 inch sky board mentioned a few posts back?  Well some of it got recycled here to make the road bed for the mountain division track.  A strip 2-7/8" wide was cut lengthwise on the table saw and this was attached on the center line 4" from the sky board

 

Ntrak specs call for the sub road bed to be 3-1/8 inches higher than the main lines.  I cut a strip of 1/2 inch plywood 2-7/8 inches wide, then drilled a series of holes with the hole saw.  I was able to make these holes with the drill press which made it easier.  This got attached edgewise on the line 4 inches from the rear of the module.  The photo above shows this from the rear of the module.  

For the actual sub road bed, another strip of the 1/2 inch plywood was attached to the edgewise to give the mountain division line the required height of 3-1/8 inches.  As there would be a siding for the station on the front side of the mountain line, several scraps 2-7/8 inches long were placed as shown in the photo above to support it.  Besides carpenters wood glue the edgewise strip was attached to the module with screws and the sub road bed was attached to edgewise strip with 7/8 inch finishing nails from a nail gun.  

Tokyo Station celebration light show

On our past couple of trips to Japan we've noticed quite a bit of construction going on at Tokyo Station.  The other day Nona found this video on YouTube.

Seems that all the re-modeling is now done and this light show was part of the celebration.  Next year will be the 100th anniversary of the station.