Further details on the Big Freight Yard....




The genisis of the Big Freight Yard with lots of storage started with an idea and email from Don Fedjur. The gist was that the biggest problem at train shows where we use a modular layout is that there is really no place for people to stage and store their trains. People wind up monopolizing the main line to build up and tear down trains.


Don was also desirous to print up the entire track plan on both sides of the track base in full size. He knew that this would allow precise track positioning and have the added benefit of unambiguously identify the track locations from underneath.


There are three 6.5' x 3' modules. One goal was to pull a 100+ car train into the yard (off the mainline) and classify the cars. This goal resulted in having a "loop" at each end, which effectively doubles the length of the yard.


The body tracks come from the standard inner module tracks, and "staging" tracks come off the standard module outer tracks. This puts the staging tracks right at the edge of the modules, the most convenient place where no one is forced to reach over the main lines while placing or removing cars.




In some later thinking of other challenges in operation, and the fact that two loops can constitute reversing loops, it was decided to drive all the "extra" tracks with autoreversers and circuit breakers.

The power for the standard inner and outer tracks flows as in a normal module, with 4 DB25 connectors per module.

All the "extra" power and control comes from module 1, the "first" module, the "control" module.

This module needs to be used "first" in that it powers the other 2 modules. It contains all the autoreversers and circuit breakers (except the 2 autoreversers for the loop and reversing section in module 3).

Power from the "standard" inner and outer tracks power the autoreversers in this way:

  • The inner tracks power 2 PSX-AR autoreversers and power the body tracks on each side of center of the module
  • Ther outer track power 2 PSX-AR autoreversers and power the staging tracks on each "side" of the module
  • There is a dual Frog Juicer set up as an autoreverser powering the loop, it is fed from an inner track power supply (far side of the module)

The output for the 2 body track circuits and the 2 staging track circuits is fed to a circular 9 pin connector, which supplies power to the subsequent modules.



If the yard is to be operated on DC, note that only the standard inner and outer tracks will function.

If one track is to be run on DC, then run the outer tracks, since you will only "lose" the staging tracks.


Set up and system check sequence:


Following this procedure will guarantee proper operation, and easily isolate any problems.


Side   6   5    4  

Module  #

  1   2   3
Side   1   2   3


 Note: if you are standing on side one, two or three, then the writing on the modules is right side up.



  1. Set the modules up in sequence, 1, 2, 3, separated by about 6 inches.
  2. Do not connect anything yet. Go back and unplug all connectors, you should have all the DB25's and circular connectors hanging free, not connected together.
  3. Read #2, this is the hardest thing for people to "get".
  4. Power module #1 via a "T" connector into the 2 DB25's at the "end" with DCC, again, no other connections or jumpers.
  5. Test the inner and outer tracks on both side of the module.
  6. If ok, proceed, if not, check your input source, check that you don't have anything else connected, if that fails, you have a broken wire between the DB25 and the tracks.
  7. Check that the loop is powered. If not OK, check the Frog Juicer, it is fed from the inner track on side 6.
  8. Now connect the two DB25's to module #2, the "middle" module. Check out the inner and outer tracks.
  9. If OK, proceed, otherwise you have a short in one of these 4 tracks in the middle module.
  10. Now connect the 2 DB25's to the 3rd and last module. Test the inner and outer tracks again.
  11. If OK, proceed, otherwise you have a short in one of the 4 tracks on this module.
  12. Test the loop and the reversing section (that connects one side of the body tracks to the other. If not OK, then check the 2 Frog Juicers.
  13. Now, we check out the body and staging tracks in module #1, check their operation. You should be able to run a DCC loco on ANY track on module 1.
  14. Really check them out, try a staging track on each side, body tracks on each side, and run through the reversing loop.
  15. If OK, then proceed, if not, check for output and shorts, go to the 4 autoreversers underneath and see if they are outputting. If not, disconnect the output wires and check if now you have output at the autoreverser NOTE: when you have the wires out of a PSX-AR, the screws on top will not conduct, they only conduct when clamping a wire.
  16. Now connect the middle module with the 9 pin connector, and make sure the body and staging tracks work.
  17. If OK, proceed, basically the only way for this to fail is damage to the round connector or it's connection to the terminal block.
  18. Now connect the round connector to module 3, and check operation of the body tracks and staging tracks. You should be able to run a loco anywhere.

Now finally you can physically join the modules. If you follow this procedure, debugging any problems will be easy, and straightforward.




staging track

staging track

std module outer track

std module inner track

body tracks "this side" of center

body tracfks "other side" of center

std module inner track

ste module outer track

staging track

staging track



the staging tracks on each side are powered from a PSXAR autoreverser/breaker, and are powered from the nearest outer track. (one each side)


the body tracks on each side are likewise powered from a PSxar, and are powered from the inner tracks.


In addition, there is a frog juicer set up as an autoreverser that powers the "loop" from the "far side" inner track (check)


Ongoing to do list:

eliminate the Tam valley juicers and convert both reversing loops to psx-ar

jumper all psx-ar to proper current (which is?)

isoloate bfy by mounting insulated joiners on all tracks at both ends



Weather Underground PWS KCACARLS78