Tehachapi Loop II

[GaryHinshaw]

Unless you value being able to throw the turnouts from a throttle or computer, rather than from the control panel, DCC control of tortoises isn't necessary or especially worthwhile in my opinion.

But we need to be able to control his turnouts too, right?   

[jagged ben]

But we need to be able to control his turnouts too, right?   

You're right.  I forgot.   

Nevermind Ed, you need to buy a Motorman! 

[ednadolski]

P.S. Can you please quit your day job and come to Vegas to paint my backdrops? Those look outstanding! 

Thanks Chris but you are being too kind.   These are just some learning experiences (a real artist would call them a "study" I suppose). I stuck them up there to see how they look under the room lighting, and just to cover up some of that naked-looking wall.  In-person they look rather shabby, especially close up, so I still have a lot of learning to do.  I am happy tho with the sky color at least


Ed

[ednadolski]

Looking good Ed!  Honestly, if the track at tunnel 10 is ~60", I'd just forgo detection in the helix and nod under to get back there when parking trains.  The track at my 5th crossing of Tehachapi Creek is 57" and I have no qualms nodding under it to get into one of my access holes.  I'm guessing you'll want to leave the fascia pretty short in that area to ease access; you could easily leave a clear view to the bottom few laps of the helix.  They'll be far enough behind the scenery to be fairly unobtrusive, and/or they could be veiled by a curtain.

With the modular construction, that area is actually going to have about 10" of vertical thickness from the track to the bottom the module base.   Because of the space constraints, I also had to plan on making a semi-circular notch on the back edge of that module, in order provide enough clearance for the helix.   Having 4 parallel tracks in there will make the inner tracks hard to see from the side whenever a train (esp. a stacker) is present on the outer track.  The only area of the staging that will be visible when the layout is in place is the lower shelf.

One of these could also be helpful:

Great idea!   My access to the helix is a duck-under at about the east Walong switch area.  There will be about 50" of clearance so that rolling chair will be a real back-saver!   In some of the pics, you can see that there is a 30" square inner access area inside the helix, which is enough room to stand up and still have some elbow space.  The plywood base in that area also serves as a shelf, to allow a place to put down cars when removing them from the track.

For the visible main line, you should at least plan to include current sensors when you run the bus wire.  You can decide later if you want to use them.  In the meantime, 9 sensors will set you back less than $20.

You mean just the coils, right?   It does sound like it would be smart to build them in from the start. 

Seeing these photos emphasizes how big your Loop scene will be! 

That is a key design goal.   I could have fit an HO layout into the same space and had basically the same proportions that my current N scale layout has.   But I really wanted to make the best possible use of the ability of N scale to build a big, wide-open scene.


Ed

[ednadolski]

From Ilmon all the way up to Tehachapi all the switches are #14 turnouts

I was wondering about that.  My layout at 80% scale size will have #12 turnouts, which seems fairly close considering that scaling down has to allow for a proportionate increase in the spacing between parallel tracks.  IIRC, the track center spacing at Walong is 14 feet, would that be correct?

Ed

[ednadolski]

Have you looked at Digitrax devices such as the BDL168 and the SE8C.

Just briefly, but these are not really an option for me since I have an NCE command station not Digitrax.

Ed

[ednadolski]

I just re-read this whole thread from the beginning and have determined that this layout is really gonna be something! 

Thanks, I do hope not to disappoint!   And if any of you dudes are ever in the Denver area, please let me know.  You are all more than welcome to check it out in person!

Not to pick nits, Ed, but on your plan on page 4 (which looks like it came from Anyrail), it looks like you have the track inside tunnel 9 completely tangent. The track there, including the entire section inside the tunnel, is actually on a slight left-hand curve from the perspective of an uphill train. The La Mesa club down in San Diego and my pike are the only two layouts I've ever seen that have modeled this correctly, though while I'm sure it was intentional at La Mesa, honesty compels me to admit that I did it strictly so the track at the bottom of tunnel 9 would come out at an angle that would allow me to cram in a semi-prototypical S-curve between there and Woodford, and I only found out the good news that it was actually prototypical months later after track was already laid.

As seen here:
http://redoveryellow.com/signals/tehachapi/033B_West_Walong_29311.jpg

Yes that foreshortened shot really emphasizes the curvature.  Chris, I have to wonder if William Hood actually planned it that way, or if he did the same sort of thing that you did? 

I did build that curve into my current Loop layout, tho I don't have any pics on hand that show it.   On the new plan, you can see the curvature if you zoom in on the full-res image and hold up the straight edge of a piece of paper against the screen.  I didn't use any particular radius, I just stretched the track together in Anyrail.  It is a very subtle curve on the plan, even tho I traced it from the prototype.
Ed

[GaryHinshaw]

In some of the pics, you can see that there is a 30" square inner access area inside the helix, which is enough room to stand up and still have some elbow space.

I was glad to see that the 2x4 was removed from across that hole. 

You mean just the coils, right?   It does sound like it would be smart to build them in from the start. 

Correct.  They can be retro-fit (as I did in some areas), but it's easier to add them as you build.

[ednadolski]

For the life of me I can only see 31 in your ASCII art diagram.   That saves you a board.  There may be a couple turnout blocks you don't really need either, but I don't think it you can save another board. 

This is my most recent version of the (stil crude) diagram (tiny print, be sure to zoom):



I've (preliminarily) identified all the blocks as 'Bnn'.  I did treat the two tracks on the lift-out as separate blocks (B1 and B15).   I could eliminate those but it would not get the count down to 32.  I am also not sure if I should separate B27 into multiple blocks, since it is too short to hold a train by itself.

Unless you value being able to throw the turnouts from a throttle or computer, rather than from the control panel, DCC control of tortoises isn't necessary or especially worthwhile in my opinion.   If you'll only ever dispatch from the CTC board, you don't need this.  But if you want to throw the turnouts at the top of staging when you've ducked into the middle of the helix, you may like having this.   

That actually sounds worth having to me.   Once the system is in place, a few extra key enhancements like this add to the overall value.

Here's my final advice on the matter (famous last words).   Buy some or all of the detector coils now, figure out how you will install them in your block wiring, and wiring the busses and blocks with a plan for detection like you said.    It's the cheapest component, and you'll be glad later if/when you decide to implement detection and signalling.

Precisely - that's what makes this the perfect time to be going over all this

Edit:  I've just realized I'll have to re-wire my Woodford module to accommodate the detection blocks, since it ties all the individual rails directly to the main bus wires.   Better now than after the scenery has gone into place! 

Ed

[ednadolski]

I was glad to see that the 2x4 was removed from across that hole. 

LOL, it sure made the space tight.... luckily I only needed it for drawing out the circles.

Ed

[John]

Just briefly, but these are not really an option for me since I have an NCE command station not Digitrax.

Ed

you can actually use the SE8Cs without the digitrax command station ..

http://www.jmri.org/help/en/html/hardware/loconet/StandaloneLocoNet.shtml#se8csigwodtcs

[Sokramiketes]

you can actually use the SE8Cs without the digitrax command station ..

http://www.jmri.org/help/en/html/hardware/loconet/StandaloneLocoNet.shtml#se8csigwodtcs

Just because you can, doesn't mean you should. 

The RR Cirkits stuff really is nice.

[bdennis]

There are plenty of examples of SE8C's and BDL168's being used with out a command station in conjunction with other DCC systems. I personally have helped 2 friends set up similar systems as they already had NCE systems to run the trains and wanted signalling..
For me it all comes down to cost to build a detection, turnout driving and signal driving system.

I agree the RRcirkits stuff is great.. I use multiple TC64's but the independent network stuff that Dick has made recently is great and worth a look.

[ednadolski]

I've been doing a bit more research on putting together a signalling system and CTC-style control panel.   I'm intrigued by the possibility of using an Arduino microcontroller to drive the signal LEDs on the layout.  The Arduino eliminates the need to implement signal logic in discrete hardware and provides a flexible programming platform that can be modified should the need ever arise.  Here is my first pass at a circuit diagram:



There is one circuit for each control point on the layout.  A Tortoise drives the turnout points and controls the frog polarity and a set of panel lamps which show the state of the turnout (Normal or Reversed).  An NCE BD20A uses current detection so that the Arduino knows when a loco enters the OS; this also drives a panel lamp on the track schematic.  The panel switches and lamps are shown on the left side of the sketch and include a DPDT for the Switch control and an SP3T for the Signal control.  The latter can be set to either Left, Right, or None. There is also a pushbutton switch with NO/NC contacts, the idea is to (approximately) emulate the Code button on a real US&S CTC panel by first setting the Switch toggle, then holding down the pushbutton for several seconds while the Tortoise actuates.  The panel switches & lamps connect to the Arduino/Tortiose/BD20 over an 8-conductor CAT5 cable (plus a separate cable for the Tortiose motor wires).

The Arduino is located in proximity with the CP and its hardware.  The signal LEDs are shown on the right side of the sketch and connect to the Arduino thru some RJ11/RJ45 cables. The signals themselves are the Showcase Miniatures parts and use the 603 RYG LEDs.

The Arduino drives each signal LED individually using its digital D0-D11 pins set to OUTPUT mode.  The Analog pins A0-A4 are configured in digital INPUT_PULLUP mode.  The Arduino reads the state of the panel switches and the BD20, and then sets each signal LED based upon a simple table.   The table is a simplified representation of the prototype signalling rules, which suffices for my needs. For example, all signals will automatically drop to red whenever a loco enters the CP, and remain so for a programmed amount of time after the block clears.  (At present, more sophisticated rules such as switch motor lock-out are not supported, but could be with a bit more software and hardware.)

Programming the Arduino is pretty simple, almost ridiculously so. All you have to do is connect the Arduino to a computer over USB and fire up the IDE program.  A single click compiles the program, downloads it to flash, and restarts the controller.  Once programmed, you don't even need the USB connection to run the board.

Here is a quick example of the Arduino in operation.  As you can see, the LED connections are trivial, as was the code to blink them:

I also have an updated version of the CTC-style panel here:



This will be a sort of 'Mini Me' panel (no more than 12 inches wide) since a more authentic one would be too large and too impractical to construct (and I already have enough concessions that break authenticity, such as swapping East and West).

This panel does not yet show any detection indicators for the hidden staging tracks, but one possibility is to have a set of ~20 bargraph LEDs on each track that show the location of the trains (that would require 80 individual optical detectors).  One benefit to that approach over a current detection one is the ability to monitor progressing trains with greater resolution (i.e., no need to keep on an 'eagle eye' watch on the panel waiting for a hidden train to trip the end-of-block detector).

More to do in the days ahead.  Stay tuned! 

Ed

[kc9jts]

I've been doing a bit more research on putting together a signalling system and CTC-style control panel.   I'm intrigued by the possibility of using an Arduino microcontroller to drive the signal LEDs on the layout.  The Arduino eliminates the need to implement signal logic in discrete hardware and provides a flexible programming platform that can be modified should the need ever arise.  Here is my first pass at a circuit diagram:



There is one circuit for each control point on the layout.  A Tortoise drives the turnout points and controls the frog polarity and a set of panel lamps which show the state of the turnout (Normal or Reversed).  An NCE BD20A uses current detection so that the Arduino knows when a loco enters the OS; this also drives a panel lamp on the track schematic.  The panel switches and lamps are shown on the left side of the sketch and include a DPDT for the Switch control and an SP3T for the Signal control.  The latter can be set to either Left, Right, or None. There is also a pushbutton switch with NO/NC contacts, the idea is to (approximately) emulate the Code button on a real US&S CTC panel by first setting the Switch toggle, then holding down the pushbutton for several seconds while the Tortoise actuates.  The panel switches & lamps connect to the Arduino/Tortiose/BD20 over an 8-conductor CAT5 cable (plus a separate cable for the Tortiose motor wires).

The Arduino is located in proximity with the CP and its hardware.  The signal LEDs are shown on the right side of the sketch and connect to the Arduino thru some RJ11/RJ45 cables. The signals themselves are the Showcase Miniatures parts and use the 603 RYG LEDs.

The Arduino drives each signal LED individually using its digital D0-D11 pins set to OUTPUT mode.  The Analog pins A0-A4 are configured in digital INPUT_PULLUP mode.  The Arduino reads the state of the panel switches and the BD20, and then sets each signal LED based upon a simple table.   The table is a simplified representation of the prototype signalling rules, which suffices for my needs. For example, all signals will automatically drop to red whenever a loco enters the CP, and remain so for a programmed amount of time after the block clears.  (At present, more sophisticated rules such as switch motor lock-out are not supported, but could be with a bit more software and hardware.)

Programming the Arduino is pretty simple, almost ridiculously so. All you have to do is connect the Arduino to a computer over USB and fire up the IDE program.  A single click compiles the program, downloads it to flash, and restarts the controller.  Once programmed, you don't even need the USB connection to run the board.

Here is a quick example of the Arduino in operation.  As you can see, the LED connections are trivial, as was the code to blink them:

I also have an updated version of the CTC-style panel here:



This will be a sort of 'Mini Me' panel (no more than 12 inches wide) since a more authentic one would be too large and too impractical to construct (and I already have enough concessions that break authenticity, such as swapping East and West).

This panel does not yet show any detection indicators for the hidden staging tracks, but one possibility is to have a set of ~20 bargraph LEDs on each track that show the location of the trains (that would require 80 individual optical detectors).  One benefit to that approach over a current detection one is the ability to monitor progressing trains with greater resolution (i.e., no need to keep on an 'eagle eye' watch on the panel waiting for a hidden train to trip the end-of-block detector).

More to do in the days ahead.  Stay tuned! 

Ed

I will admit that I am not too familiar with the Arduino module itself, but that being said I can easily see what you are planning on doing and honestly, it looks like a simplified version of what I deal with every day on the real railroad.  Do you plan on having a standard Red-->Yellow-->Green aspect progression?  I ask as I see yellow bulbs in all the signals but the only one that seems to show in the table is the facing signal (H1/H2) if lined into the siding.  Good work and keep us updated!