SP Lufkin Sub Engineering Report

[SSW7771]

I am starting this topic to introduce and document the construction of my new N scale layout. I hope you will enjoy the ride.

The original goal was to model the operations Southern Pacific’s Lufkin Sub from Houston, TX to the yard in Lufkin, TX. However this would require a lot more space than I currently have available. After careful research, I have narrow down the model portion to the segment from Leggett, TX to Corrigan, TX. This will allow for interesting operations and allow for future expansion in either direction.  Below is a quick and dirty about the layout:
   
Scale: N Scale
Railroad: Southern Pacific
Region: East Texas
Era: 1990-1996 (Pre UP)
Layout Space: Garage
Layout Construction: Primarily Free-moN Modules
Operations: Local switching with road freights
Industries (on layout): Aggregates, Wood Products, Wood Chips, Livestock Feed

The layout will focus on the operations of the Leggett Switcher which was based in Leggett, TX and worked the various industries in Livingston, TX, Moscow, TX, and Corrigan, TX. This includes the interchange with the Moscow, Camden, and San Augustine Railroad at Moscow, TX. Additionally, several road freights setout and pickup cars at Leggett, Moscow, and Corrigan. Other road freights include unit rock trains, petrochemical, and TOFC.

Here is a quick history and backstory on why I chose to model the SP. I was born into a railroad family both my grandfather and my father both worked for the SP in Texas. I grew up in Houston and spent a lot of time as a kid with my Dad on various railroad related activities from hanging out at the Englewood Yard to driving up to Lufkin to see derailments. My Dad worked as a locomotive engineer with SP out of Houston in all directions, however spent a significant amount of time the Lufkin Sub. So I am cheating a little by having access to someone who worked the same line as the modeled portion.

In upcoming post I will go into more detail for each model location.
 
Without further delay here are a few prototype photos. More can be found in my railimages albums.





Marshall

[coldriver]

Sounds like you're ready to jump in with both feet Marshall!  Do you have a track plan you can post?

[Denver Road Doug]

Great to hear more about your concept.  Did a little Google earth stalking and saw some interesting industries just on the northside of Corrigan, also what appears to be some type of lumber products facility north of Moscow...still rail served in the 1996 "time machine" view on Google Earth. (a great resource but some areas were blacked out)  Of course, you have no shortage of information by which to create your scheme with your family and personal experiences.      Anyway, looks like some great switching opportunities and nice scenery potential.

[SSW7771]

The track plan is not finalized however, below are track diagrams for the modeled segment. Since I am going to build the layout in Free-moN modules each location will be its own module or group of modules. This will allow me to share several modules at local shows and give me the flexibility to relocate when we move.

The diagrams represent the prototype during the modeled period. However, to help improve switching I plan to move the treated lumber plant in New Willard into Leggett. I also plan to reinstate the house track that the prototype removed in Moscow which would give me a team track.



Leggett: Only siding modeled that is long enough to hold a road freight. House track is used to hold the Leggett Switcher power, but should have room to allow for a "team track" spot.

Moscow: Second longest siding on the layout. Siding is used for storage and to build LUHOM or the Termite Train as crews called it. This where the SP interchanged with MCSA. Primary traffic interchanged is plywood and woodchips.



Roderick: Less than half mile east of Moscow, home to Kirby Lumber which loads woodchips. At the high point of woodchip operations it would get switched twice a day.

Corrigan: In town there is a short siding used for storage and a team track. East outside of town it another short siding with spurs that serve Champion Plywood and Louisiana Pacific Wafer Board. Champion also produces woodchips.



Possible Future Expansions:
- East to Diboll: next mainline siding also interchange with the Texas Southeastern
- Expand to include the MCSA mainline and the plywood mill at Camden

Marshall

[SSW7771]

I have been busy with work and etc. lately, but the long weekend allow for some train time. I decided to build a test 1'x4' module using steel studs as a proof of concept. Working with steel studs was surprisingly easy all you need is safety glasses, gloves, and tin snips. I used self tapping sheet metal screws to fasten everything together. I built the module a little differently from others who are using steel studs for benchwork:
 1. I used the studs to run the length of the module to capitalize on the strength of the stud vs the track
 2. Track was used for support at the ends and middle
 3. The edges are facing outward so they will be protected when the endplates and fascia are installed

I also load tested the module with 100 lbs in the form of bagged concrete. The deflection was just under 1/8"! Overall I really like the steel studs.   

[Scottl]

Isn't the steel rather heavy to work with?

[SSW7771]

Isn't the steel rather heavy to work with?

It is not heavy at all. The test module weighs less than 2 lbs. Also it is very rigid and easy to get square.

[SSW7771]

For the first time in a while I had some free time. I decided to mock-up the first set of modules that focuses on the town and plywood mill at Corrigan. I started off by doing a full size mock-up on a sheet of particle board in the garage and then transferred my mock-up into XtrackCAD. I used printed turnout templates for the mock-up along with a few boxes, unitrack, and rollingstock. Below is a picture of the mock-up.


Below is the trackplan. The portion around the walls is my initial idea which is closer to the actual prototype. However, I also drew any alternative (in the center) with Corrigan combined. I am not quite sure how I feel about the alternative version. It takes up less space leaving more room for expansion, but may be too crowded. I am open to any thoughts or comments.

[Denver Road Doug]

Cool!  I missed your post about the benchwork...nice.

Regarding Corrigan...   After perusing Google Earth, I say combine it.  The "northeast" quadrant of the town, as viewed with the main forming the west-east X-axis, (and Ben Franklin St. the somewhat skewed Y) is relatively barren of town, compared to the other three.  So, in my mind it is a more natural move to slide the industrial area railroad west into that area without taking much away from the overall scene.   My two cents. 

[C855B]

Cool!  I missed your post about the benchwork...nice. ...

Same here, Doug... I completely missed a very valuable post.

Marshall - Thank you for confirming the direction I was going with steel studs in benchwork. Reversing the usual relationship between tracks and studs is genius. I will likely be following your lead. What are you doing with the web part of the tracks where they join? Bending it over with tinsmith's pliers, or snipping out completely? I visualize bending to 90' with another fastener through the folded web.

Scott, steel studs are about 1/4 the weight of the equivalent white pine 2x4. They are very strong and bear an incredible amount of weight perpendicular to the web, as Marshall demonstrated. Biggest issue is poor resistance to twisting. Beyond more than about a 6' span you're dependent on something else to keep things in line... like drywall or other panel material fastened to the face. Marshall's test with the center support at 2' was a bit of overkill, but it's an excellent demonstration. You might recall in the GC&W thread that I'm using steel 2x4s as structural support for the grid ceiling.

For benchwork I am testing steel studs that are 2x3 and even 2x2 equivalents, probably settling on 2x3 at this point with 2x2 as truss ties where needed. I prefer the smaller profile for more working room underneath. Similar to Marshall, I've been using Tek self-drilling screws, but am likely to change that plan to using the screws as an assembly step, backing them out one at a time once things are square and replacing with pop rivets. Since there will be a lot of work underneath considering wiring and switch machines, there is incentive to reduce any hidden pokey-thingies, and the near-flush head will simplify things up top.

[Lemosteam]

Although you are using two tabs to attach on the top and bottom with the cross piece channels, it may be a good idea to bend a flange on the channel in it's web area to mate flush with the inside of the studs with some screws there.  I like the out-facing channel as wiring can be laid in there for controls and such.  I have long considered this to be a better alternative to wood. Wonder if there is a weight differential?  What will be your solution for leg attachment?

[C855B]

There is a large weight difference. Weights of 10' studs I have on hand:

  #2 white wood - 10.3 lbs.
  22 gauge steel - 5.0
  24 gauge steel - 3.8

So correct my "1/4" for steel to one third to half of wood.

[SSW7771]

Regarding Corrigan...   After perusing Google Earth, I say combine it.

After sleeping on it, I think I am going to combine Corrigan. You are right that it really does not take away from the scene.

What are you doing with the web part of the tracks where they join? Bending it over with tinsmith's pliers, or snipping out completely? I visualize bending to 90' with another fastener through the folded web.

For the test module I just snipped it along the top and bottom flange an bent it 90 degrees. After reviewing the assembly I did not feel that another fastener on the web was necessary. On production modules I may completely remove the web section. Also, I like the idea of using rivets, but this was just a proof of concept build so I used what I had on hand.

Biggest issue is poor resistance to twisting. Beyond more than about a 6' span you're dependent on something else to keep things in line... like drywall or other panel material fastened to the face. Marshall's test with the center support at 2' was a bit of overkill, but it's an excellent demonstration.

Correct, twisting is an issue with steel studs, but can be easily addressed with the center supports cut from the track like I did on the test module. For a 4' module the center support is not necessary under normal model railroad loads, but it was needed for the 100 lbs test load.

Wonder if there is a weight differential?  What will be your solution for leg attachment?

There is a weight differential compared to wood 2x4s as C855B has already noted. However, if you compare this other lightweight construction techniques it appears to be about the same or lighter. The steel does have the added benefit of being dimensionally stable compared to wood which will handle temperature changes much better. Also the steel is very rigid and can take a good beating which is good as these modules will be handled frequently.  I have not worked out the leg attachment yet; the legs and endplates are the next step of the test module build.

[C855B]

It's the dimensional stability that drives my interest in steel studs, the lower profile of 2x3 while retaining strength is a secondary benefit for my work. Wood's biggest problem is not temperature but humidity and its effects on the wood fibers. Since changes in temp and humidity are frequently closely associated a lot of folks think it's the temp differences.

Yes, there's not much weight difference compared to, say, benchwork built from 1x4 wood. A few years ago I was experimenting with cabinet-grade plywood, dadoing slots and drilling large holes to lighten the structure, following old-school aircraft construction techniques. It reduced weight by about 40%, but was a boatload of work. I think I burned - literally - burned through three hole saws.

Somebody mentioned legs. I have two thoughts at the moment, first is making a box girder out of 2x3 metal studs with a wood block insert at the bottom to hold a T-nut or threaded insert for an adjustable foot. Second is PVC pipe; I've been doing a lot of experimentation with 1-1/4" 160psi irrigation pipe. It is much lighter than regular ol' Sched 40, but uses conventional 1-1/4" fittings. I had been filling it with aerosol insulating foam to reduce flex, but determined it was unnecessary. Foot is a press-fit wooden plug secured with polyurethane ("Gorilla") glue, I'm still messing with fastenings for the top. For the permanent layout it will likely be a two-hole conduit clamp.

[chuck geiger]

Love me some Texas SP
http://www.frolin.net/mmgs/pictures/20060128/